US2253201A

US2253201A - Magneto with protective mechanisms

Info

Publication number: US2253201A
Application number: US369028A
Authority: US
Inventors: Wolfgang E Schwarzmann; Strniste Charles
Original assignee: American Bosch Arma Corp
Current assignee: Ambac International Corp
Priority date: 1940-12-07
Filing date: 1940-12-07
Publication date: 1941-08-19
Anticipated expiration: 1958-08-19

Description

Aug. 19, 1941.

W. E. SCHWARZMANN ETAL MAGNETO WITH PROTECTIVE MECHANISMS Filed Dec. 7, 1940 0 E WEE? BY Java/1;:

A Qua.

AT'TORN EY Patented Aug. 19, 194i UNITED STATES PATENT OFFICE.

- 2,253,201 v MAGNETO wrrn rao'rso'nvn mscrmmsms Wolfgang E. Schwanmann, Longmeadow, and Charles Strniste, Agawam, Masa, assignors to American Bosch Corporation, Mass., a corporation of New York Springfield,

Application December '1, 1940, Serial No. 369,028 12-Claims. (Cl. 171-209) The present invention relates to magnetos with protective mechanisms normally arranged for electric spark ignition in internal combustion engines, and it relates particularly to magnetos with permanently connected generating windings,

and with'disabling circuits of the kind which automatically renders themagneto electrically incapable of generating ignition voltages upon removal of a part normally fastened to the magneto and whichmaintains such inoperative condition of the magneto until the removable part is restored to normal position.

It has happened after removing the cable connector of the manually-operative grounding switch from themagneto on an airplane, for purposes of inspection or repair, that the connector was inadvertently not replaced in position, whereupon closure of the switch to presumably prevent ignition while turning the propeller by hand, resulted fatally when the engine started into operation unexpectedly. The primary object or this invention is to provide for magnetos automatic protective mechanism therefor, including any removable part whether for a manuallyoperative grounding switch or some other elec- .trical device as a vibrator for starting ignition or some mechanical device or member generally as a shield or cover, to prevent that or other unex-,

pected occurrence by automatically rendering the magneto electrically incapable oi! generating ignition voltages upon removal of the part and for maintaining the magneto in that inoperative con-- ment in application to an electrical device, not

only does the cable connector, when removed, permit the spring to-automatically short circuit the circuit interrupter of the magneto, but, when restored to position on the magneto, it acts to electrically connect the live terminal of the circult interruptertothe electrical device. I e Other objects will appear iromtheviollowing description taken in connection withthe accompanying drawing showing magnetos with proteceach arranged, tor example, to short circuit the circuit interrupter of the magtive mech neto by releasing a biased spring into engagement with the grounded interrupter housing upon re'-,

moval of an'electrical connector or other part normally fastened to the housing. In the draw- Fig. 1 shows, partly in section, and partly diagrammatically, a plan view of a multicylinder high tension magneto having a manually-operative grounding switch; Fig. 2 similarly shows another form of the protective mechanism applied generally to a magneto and arranged for association with any electrical device in accordance with the invention; and Fig. 3 shows a magneto with a removable part associated with the cover of the interrupter housing.

Referring to theembodiment of Fig. 1, the magneto generally indicated by the reference numeral I has permanently. connected. primary and secondary generating windings 2 and 3, respectively, and a housing 4 fo'rythe circuitinterrupting mechanism arranged in the, circuitot the primary winding, all of well known construction and arrangement. The interrupter-mechanism includes a circuit interrupter having a pivoted 2 spring-biased intermediate lever 5 periodically operated by the lobes of cam 6 fast on shaft I of the rotor of the magneto. Upon eachsuch;

operation, the lever B engages the deflectable spring lever 8 and separates its interrupter coritact 9 from the cooperative interrupter contact I III which ismounted on the bent-up portion H 1 of plate member I! adiustablymounted on the interrupter disc I3. This disc is mechanically secured in adjustably timed position and electrically connected to the grounded housing I.

I and ,the lever 8 is supported from the terminal generally indicated by II, which being electrically insulated from disc II, as will-be described more fully hereinafter in connection with Fig. 2, 40 forms the normally live terminal of the circuit interrupter. The condenser i5 is connected by the conductors l6, l1 between disc II and terminal H to electrically shunt the interrupter contacts Q, It. The live terminal I4 is connected by wire II to oneend of primary winding 2 and one end of secondary winding 3, the other end of the primary winding being grounded at I! and the other end of the secondary winding being con nectedto the distributor rotor 20 for sequential distribution of the ignition voltages, generated by the magneto upon separation oi-the contacts I, "ll,,to the insulated electrodes ofthe grounded sparkplugs II in the well known manner.

to thelive terminal ll of the interrupter is a conducting support 122, and also connected to this terminal and arranged around this support is a flat spring 23 which is biased toward engagement with the grounded housing 4 as indicated by the broken lines, in which grounded position the normally live terminal 44 is grounded and renders the magneto electrically incapable of generating ignition voltages upon periodic separation of the contacts 9, l0. However, the coil spring 24, which is strong enough to overcome the spring 23, and which is secured at its inner end to metal terminal 25 of the removable connector 26, holds the spring 23 in. its normally operative position shown in full lines out of grounding engagement whenever the connector is in place in the housing 4, but upon removal of the connector from the housing permits the spring 23 to move automatically into grounding position and to maintain that grounded position as long as the connector is removed. This terminal 25 of connector 26 is electrically insulated from the housing as illustrated and s electrically connected in any suitable way to the central conductor 21 of the insulated and shielded cable 28. This cable is eelctrically'connected to the manually-operative grounding switch 29 of the magneto and is held firmly in th connector by the rubber grommet 30 which is compressed bythe nut 3| releasably locked in position by the spring fingers 32. The complete connector 26, with its spring 24 and terminal 25 and with the attached cable 23, is readily removable and replaceable by screwing it out of and into engagement with the threaded nipple 33 of the housing 7 4. Thus, with'the parts in normal position as shown in Fig. 1, the live terminal l4 of the in terrupter is electrically connected to the grounding switch 29 which then may be operated at will to ground the magneto-todepriv'e the engine of ignition and, with the connector removed from a magneto installation on an engine to inspect or repair the magneto, connector or magneto grounding switch or for any other purpose, the interrupter is automatically and permanently grounded on the housing 4 by the spring 23, as shown in Fig. 1 in broken. lines, whether the magneto grounding switch 29 is closed or open.

In the embodiment of Fig. 2, the interrupter housing 4' contains the same or other suitable circuit interrupting mechanism and the wire I 8 leading from the ignition coil of the magneto through an opening at 34 in the disc l3 to the live terminal l4. As in the embodiment of Fig. 1. this terminal comprises an upstanding metal post 35 fastened to disc l3 and insulated as indicated from the bolt 36 and nut 31. In this case, however, the automatic grounding spring is in the form of a closed loop 38 having its ends, fastened and electrically connected to the live terminal l4 and being biased toward engagement with the grounded housing 4 as indicated in broken lines. Also in this case, the removable connector 39 has a conducting terminal 4D which is insulated as shown from the metal nut 4| and the externally threaded nipple 42 but electrically connected in any suitable way to the central wire 43 of the cable 44, and which in normal position of the connector on the housing holds the spring 38 in the position shown in full lines out of grounding engagement with the housing. The wire 43 may be connected to a manually-operativ magneto grounding switch as in Fig. 1 or to any other electrical device as a vibrator for supplying pulsating currents to the ignition coil to start the engine into normal operation by a shower of sparks in the well known manner. Thus, as in the embodiment of Fig. 1, when the connector 39 isin normal position as shown, the live terminal l4 of the interrupter is electrically connected to the wire 43 and the magneto is in electrical condition to generate ignition voltages, but upon removalpf the connector the interrupter is automatically grounded by the spring 38 and the magneto remains electrically incapable of such generation until the connector is replaced in normal position on the housing.

In the embodiment of Fig. 3, the removable part is the cover 45 of the interrupter housing 46. This cover has fastened to it a member 41 of insulating material which, when the cover is in normal position, over the end of the housing as indicated, holds the spring 23 in the full line position to render the magneto electrically operative, and which, when the cover is removed as for inspection of the interrupting mechanism, allows the spring to automatically assume its grounding position in engagement with the housing 48, so as to render the magneto electrically incapable of generation and to maintain that inoperative condition until the cover is replaced. If desired, a magneto grounding switch of some suitable arrangement can be added to this embodiment to cut off the ignition at will.

It will be apparent that the electrical circuit containing the spring 23 of Figs. 1 and 3 or the spring 38 of Fig. 2 constitutes for the magneto in each case a disabling circuit including a switch comprising the grounded interrupter housing as one pole and the engageable end of the spring as the other pole. Since, as shown in Fig, 1, the primary winding 2, secondary winding 3 and interrupter lever 5 are each grounded on the interrupter housing 4, this disabling circuit acts, when the spring engages the housing upon removal of the removable member, to short circuit the generating winding and the interrupter.

The operation of the three embodiments specifically described herein, will be understood from the foregoing. As will be apparent to those skilled in the art, the magneto may be rendered incapable of generating ignition voltages upon removal of a part of the magneto, or a part of a device or member associated with the magneto, by short circuiting the primary circuit in the case of low tension and high tension magnetos, or at least a portion thereof as for instance the circuit interrupter, or by a portion at least of the high tension circuit in the case of high tension magnetos, by utilizing a grounded disabling circuit for th short circuiting arrangement in a magneto, not only is no partof any generating circuit disrupted to disable the magneto, but only one live terminal of the circuit need be engaged. By short circuiting the low tension winding, there is the additional advantage of operating upon a low tension connection, and by short circuiting the circuit interrupter, there is the further additional advantage of having a live terminal readily available for the purpose and also of utilizing the terminal suitable for connection to a magneto grounding switch or a starting vibrator or other electrical device. Also it Will be apparent that the magneto may be for engines of any number of cylinders and of the rotary, oscillating or other type, and also of the type in which generation of ignition voltages occurs upon closure of the circuit interrupter as well as upon the opening thereof. Therefore, the terms of the appended claims are intended to be interpreted in their broadest sense.

Having thus described the invention. what is claimed is: v

1. In combination, a magneto having a permanently connected circuit normally operative to generate ignition voltages, a disabling circuit which is effective to render the magneto inoperative by rendering the generating circuit electrically incapable of such generation and which includes an automatic switch automatically opera- I tive to a position to render the disabling circuit eifective, and a removable part normally fastened to the magneto and having means which upon removal of the part from its normal position releases the switch for its automatic operation and which upon. restoring the part to its normal position automatically renders the switch inoperative and thereafter keeps it inoperative, whereby removal of the part automatically renders the magneto inoperative and maintains it in that inoperative condition until the part is restored.

2. In combination, a magneto having a permanently connected circuit normally operative to generate ignition voltage, a disabling circuit which is effective to render the magneto inoperative by rendering the generating circuit electrically in- 5. In combination, a magneto having a high tension circuit and a permanently connected low tension circuit operative to generate ignition voltages, a disabling circuit which is elective on the removal of the part from its normal position recapable of such generation and whichincludes an automatic switch automatically operative when unrestrained to a position to-render the disabling circuit effective, and a removable part normally fastened to the magneto and having means which upon'removal of the part from its normal position releases the switch for its automatic operation and which upon restoring the part to its normal position automatically opens the switch and thereafter holds it open, whereby removal of the part automatically renders the magneto inoperative and maintains it in that inoperative condition until the part, is restored.

3. In combination, a magneto having a permanently connected circuit normally operative to generate ignition voltages, a disabling circuit which is effective to render the magneto inoperative by rendering the generating 'circuit electrically incapable of such generation. and which includes a spring biased toward a position to render the disabling circuit eifective, and a removable part normally fastened to the magneto and having meaiis which upon removal of the removable part from its normal position releases the spring for automatic operation to its effective position and which upon restoring the part to its normal position automatically moves the spring out of its effective position and thereafter holds it out of such p0siti0n,-whereby the removal of the removable part automatically renders the magneto inoperative and maintains it in that inoperative condition until the removable part is restored.

4. In combination, a magneto having a permanently connected circuit normally operative to generate ignition voltages, a disabling circuit which shunts a portion at'least of the generating circuit to thereby render the magneto inoperative by rendering the generating circuit incapable of such generation and which includes an automatic switch automatically operative to render the disabling circuit effective, and a removable part normally fastened to the magneto and having means which upon removal of the part from its normal position releases the switch for its automatic operation and which upon restoring the part to its normal position automatically renders the switch inoperative, whereby removal of the part automatically renders the magneto inoperative and maintains it in that inoperative condition until the part is restored.

leases the switch for its automatic operation and which upon restoring the part to its normal position automatically renders the switch inoperative and thereafter keeps it inoperative, whereby removal of -the part automatically renders the magneto inoperative and maintains it in that inoperative condition untilthe part is restored.

6. In combination; a magneto having a permanently connected circuit including a circuit interrupter normally operative to generate ignition voltages, a disabling circuit'which is effective to render the circuit interrupter electrically inoperative and thereby render the generating circuit electrically incapable of such generation and which includes an automatic switch automatically operative to afposition torender the disabling circuit effective, and a removable part normally fastened to the magneto and having means which upon removal of the part from its normal positionreleases the switch for its automatic operation and which upon restoring the part to its normal position automatically renders the switch inoperative and thereafter keeps it inoperative, whereby removal of the part automatically renders the magneto inoperative and maintains it in. that inoperative condition until the part is restored.

'1. In combination, a magneto having a permanently connected grounded circuit normally operative to generate ignition voltages, a disabling circuit which is connected to a live ter-- minal of the generating circuit and is arranged to render the magneto inoperative by shunting its generating circuit and which includes an automatic switch automatically operative to engagement with a grounding part, and a removable part normally fastened to the magneto and having means which upon removal of the removable part from its normal position releases the switch for its automatic operation and which upon restoring the part to its normal position automatically moves the switch from its grounding position and thereafter holds it out of such position, whereby the removal of the removable part auto,- matically renders the magneto inoperative and maintains it in that inoperative condition until the removable P rt is restored.

8. In combination, a magnetohaving a permanently connected circuit including a permanently grounded circuit interrupter normally operative to generate ignition voltages, a disabling circuit which is connected to a live terminal of the circuit interrupter and is arranged to render the magneto inoperative by shunting the circuit interrupter and which includes an automatic switch automatically operative to engagement with a grounding part, and a removable part normally fastened to the magneto and having means which upon removal of the removable part from its normal position releases the switch for its automatic operation and which upon restoring the part to its normal position automatically moves the switch from its grounding position and thereafter holds it out of such position, whereby the removal the removable part automatically renders the magneto inoperative and maintains it in that inoperative condition until the removable part is restored.

9. In combination, a magneto having a permanently connected circuit including a circuit interrupter mounted in and electrically connected to an interrupter housing and normally operative to generate ignition voltages, a disabling circuit which is effective to render the magneto inoperative by rendering the generating circuit electrically incapable of such generation and which includes a spring fastened to a terminal of the circuit interrupter and biased toward engagement with the housing, and a removable part normally fastened to the housing and having means which upon removal of the part from its normal position releases the spring for its automatic operation and which upon restoring the part to its normal position automatically moves the spring out of engagement with the housing and thereafter holds it in that position, whereby the removal of the removable part automatically renders the magneto inoperative and maintains it in that inoperative condition until the removable part is restored.

10. In combination, a magneto having a permanently connected circuit normally operative to generate ignition voltages, an electrical device associated with the magneto and having a connector removably fastened to the magneto, and a disabling circuit which is effective to render the magneto inoperative by rendering the generating circuit electrically incapable of such generation and which includes an automatic switch automatically operative to a position to render the disabling circuit effective, the connector having means which upon removal of the connector from the magneto releases the switch for its automatic operation and which upon restoring the connector to the magneto automatically renders the switch inoperative and thereafter keeps it inoperative, the connector also having means for electrically connecting the electrical device to the generating winding when the connector is fastened to the magneto.

11. In combination, a magneto having a permanently connected circuit including a circuit interrupter grounded in an interrupter housing and normally operative to generate ignition voltages, a disabling circuit which is effective to render the magneto inoperative by rendering the generating circuit electrically incapable of such generation and which includes a spring connected to a live terminal of the circuit interrupter and biased toward engagement with the housing, and an electrical device associated with the magneto and having a connector removably fastened to the interrupter housing, the connector having a conductor which when the connector is fastened to the housing holds the spring out of engagement with the housing and electrically connects the spring to the electrical device and which when, the connector is removed from the housing releases the spring for its automatic operation.

12. In combination, a magneto having a permanently connected circuit normally operative to generate ignition voltages, a disabling circuit which is effective to render the magneto inoperative by rendering the generating circuit'electrically incapable of such generation and which includes an automatic switch automatically operative to a position to render the disabling circuit effective, and a removable mechanical part of the magneto having means which upon removal of the part from the magneto releases the switch for its automatic operation and which upon restoring the part to its normal position automatically renders the switch inoperative and thereafter keeps it inoperative, whereby removal of the removable part automatically renders the magneto inoperative and maintains it in that inoperative condition until the part is restored.

WOLFGANG E. SCHWARZMANN. CHARLES STRNIS'I'E.