US2394234A - Magneto - Google Patents

Description

Feb. 5, 1946. w. D. CROCKER ETAL 2,

I MAGNE'IO v 7 Filed Oct. 50, 1943 2' Sheets-Sheet x 4 INVENTORS Mum/w 0. mac/r5? & FAAA/K s. c0:

Qua-.1

A T TORNEY Patented Feb. 5, 1946 UNITED STATES PATENT OFFICE William D. Crooker, Suiiield, -Gonn., "and Frank :SrCoe, Springfield, Mass, assignors to American Bosch Corporation, Springfield, Mesa, a corporation ofNew York Application otob'er '30, 1943, Serial 580. $08,350

Claims.

This invention relates to 'multicylinder ignition magnetos for internal combustion engines, oithe type having a generator-shaftcarryingthe generator rotor and a cross "shaft gear driven by the generator shaft and carrying the distributor rotor and preferably the circuit breaker also as generally disclosed in Patents 2,198,754 and 2,260,663.

One object of our'invention istojprovide 'anenclosed magneto or this type "capable, if desired, or safely operating at high altitudes, say 35,000 feet or more, as for instance on combatairplanes. To assist in doing this, the magneto is adapted to drive by its cross shaft asuperchargin'g'pump or air 'conrpressorwhioh, together with a sectionalized portion of the "frame incorporating the air inletand filter iorthe pump, are replaceable with a cover plate and an associated closedirame'section in case the magneto is to "be supplied with compressed air "from the engine supercharger or from some other outside source, or in case the magneto is intended to operate without supercharging.

Another object'is to "provide improved means in such "a magneto i'or maintaining the direction of rotation of the cross shaft while reversing that o! the generator shaft to permit different installations ofthe magneto on the engine.

Another object is to provide an interior connectlon between the *hig'htension terminal of the ignition coil and the distributor rotor located on opposite sides of the "generator shaft of 'a single-spark magneto, whereby no outside high tension wire is required for the purpose.

Another object is to provide an improved distributor arrangement for a magneto ofthe high tension type, whereby electricalflashover, corona effects and'leakage's are reduced in occurrencea'nd degree at substantially all altitudes of operation.

Other objects and advantageswill appear from the following description of the preferred embodiment of an exemplary l4-cy1inder single-spark high tension magneto having its magnetic rotor vertically arranged for drive in either direction of rotation from a four-stroke internal combustion engine, taken in conjunction with the accompanying drawings, in which:

"Fig. l is a central vertical section, partly in elevation and partly broken away, of the magneto with its supercharging pump attached; Fig. "2 is a bottom elevation of the interior electrical connector between the high tension terminal of the ignition coil and the distributor rotor; Fig. 3 is a view similar to that of Fig. 1, of an'upperpart of the magneto with the pump replaced by'a cover plate for the irame; and Fig. 4 is an enlarged central vertical section, partly in elevation, :of the cross shaft, with the bevel gear reversed in position thereon for the opposite rotational 4directionof the generator'shait.

Referring to Figs. 1 and the magneto frame comprises the base mounting flange 1 iastened to the main housing-member 2 which hasintegml brackets 3 and t and detachable coil cover plate 5, top cover plate 6, distributor zplate housing member #1, supercharging pump 8 with its :airfilter frame section B, and shelf 10. generator rotor, comprising the vertical shalt H and the sheet steel body II, with our radial poles similar'to that inFig. 4 of Patent 2:305348, is journale'd in bearingscarr ied by "the flange l and shelf -i'il. The -lower-end-oi this shaft is provided with a timing coupling i3 and gear M of well known kind fast tothe shaft H and driven-by the engine at crankshaft speed. On' theupper end of this shaft is iastened a'beve'l pinion i5 meshed *with abevel gear it which is keyed to'the horizontally extending cross shaft ll and which provides a gear-ratio of 8/14 soas to rotate the cross shaft at engine cam shaft spe'ed. brackets 3 and 4 can'y thebearin'gs for the cross shaft "11 with their-oil seals, and rorm withthe Shelf ill 'a gear compartment 8 which 15 -'sealed below'by anvil-seal.

The magnetic stator oi the generator comprises a sheet steel structure comprising pole shoesand arms *for the permanent magnets, and ior the coil it! having a'laminatedcore -20, similar to that ofFig. 1 of Patent 2,298,652. Thiscoil has-primary and secondary-windings of well known con struction, and has a. high tension terminal II which is electrically connected interiorly of the magneto and across the generator compartment 22 to the insulated fixed distributor ring 23 on the opposite side of the shaft 11 by a-shrouded cross connector 24 "having the conductor 25 and the spring-pressed brush it. This cross connector extends generally horizontally-and is detachably fastened by screws at 2'1 to the stator structure, its :nose at the other end "being supported in a socket '28 of the fixed distributor ringthrough'the intermediary of a synthetic rubber bushing 29. In this position the spring-pressed brush -16 engages the ring "23 in electrical contact therewith. Thus notwithstanding that the cross cormector 2! may 'bereadily detached for servicing, reliable electrical connection -is maintained between the coil terminal 21 andthe distributor ring 28 on oppositeysi'des of the generator shaft l1 under the' severe vibration'experienced on airplanesmnd furthermore any changes in the length of the cross conductor in shrinking after molding or during excessive temperature variations in operation are compensated by the brush 26. Furthermore by arranging the cross connector wholly interiorly of the magneto within the generator compartment 22, which is supercharged in operation at high altitudes, electrical breakdown from the conductor to the frame and other grounded parts is avoided.

The distributor rotor is fastened to the cross shaft H and carries a metal insert 3| with electrodes 32 and 33 riveted thereto and forming in effect a single electrode. The electrode 32 is in jump spark relation with the stationary ring 23 which embraces the shaft IT at one diameter, and electrode 33 is in jump spark relation with the fourteen stationary electrodes 34 of the distributor plate 35 arranged about the shaft IT in a circle of a diameter greater than that of the ring 23. These distributor parts are arranged in the distributor compartment 36 which communicates with the generator compartment 22 so as to be supercharged therewith. The electrodes 34 are electrically connected to shielded cables of well known kind extending in the wellknown way through an ignition manifold to spark plugs in the respective engine cylinders. By this arrangement of the cross connector 24, stationary insulated ring 23 and distributor rotor 30, the electrical spacing between the high tension conductor and grounded parts of the magneto, and between the ring 23 and the electrodes 34, are increased over that usual in other distributor arrangements within like dimensions, and therefore flashover, corona effects or leakage do not occur to the same extent without supercharging until greater altitudes of operation are attained.

The circuit breaker assembly is mounted around the cross shaft |l directly over the coil |9 on the same side of the generator shaft II. This assembly comprises a breaker plate 31 which is fastened to the bracket 4 in circularly adjustable position around the cross shaft and which carries the breaker contacts and deflectable lever cooperative with the 14-lobe cam 38 fast on the cross shaft, all of well known construction and arrangement. The live terminals of the primary winding of the coil l9 and of the breaker are connected by an insulated Wire 39 extending directly upwardly. In this way the primary and secondary connections of the magneto are kept distant from each other, and the circuit breaker assembly is made accessible for service upon removal of the supercharging pump 8 as hereinafter described.

The supercharging pump 8 is arranged to supply compressed air to the generator and distributor compartments 22 and 36, a suitable discharge opening or leakage place or places being provided in the magneto frame in the well known way. The pump is of the well known rotary type with radially movable vanes carried by a shaft 40 journaled in bearings coaxial with the cross shaft H. The srHft 40 is driven by the shaft H by an axially disengageable coupling 4| of well known kind, the arrangement being such that the pump 8 with its shaft 40 and coupling 4| may be assembled to and disassembled from the magneto as a unit. Air at the pressure of the surrounding atmosphere is drawn by the pump through an inlet 42, in the frame section 9, and thence through the air filter 43 and inlet passages 44 and 45, and is discharged by the pump into the generator and distributor compartments through the outlet passages 45 and 41 to thereby maintain appropriate air pressure within the magneto at any altitude of operation.

Whenever desired, as for instance when the magneto is to be supercharged from the engine supercharger or other source of compressed air, or is not to be supercharged at all because of intended operation below the critical altitude, the pump 8 may be removed merely by withdrawing the fastening screws as 54 (Fig. 3) and disengaging the coupling 4|. The section 9 of the frame,

carrying the air inlet passage 42 and filter 43,

is then removed also. The magneto frame is then closed by fastening thereto the cover 48 with its intermediate section 49, as shown in Fig. 3.

In this way the magneto is readily convertible from one with a supercharging pump to one without it, proper connection through the cover plate 48 or the frame section 49 then being provided when supercharging from an outside source is used, or a ventilator in that cover plate or frame section being provided when normal ventilation without supercharging is depended upon. In this way there is provided a flexible and convenient conversion of the magneto to suit the exigencies of its operation.

The arrangement of the parts in Fig. 4 is identical with that of Fig. 1 except that the bevel gear l6 and the spacing sleeve 59 are interchanged in position on the cross shaft so that with the reverse direction of rotation of the generator shaft II, the supercharging pump shaft 40 rotates in the same direction as before to accord with its preferred rotation. Likewise the breaker cam 38 and the distributor rotor 30 rotate as before. The result is accomplished by making the cross shaft symmetrical for a sufficient part of its axial length on the two sides of the axis of shaft II, and by providing for the proper timing of the breaker cam, to take care of the proper edge distance between the rotor and stator poles of the generator upon interruption by the breaker preferably by means of a second keyway 5|, in the cross shaft in addition to the keyway 52 and slightly displaced angularly therefrom, for the key 53 in the gear Hi. In this way, the magneto may be changed from clockwise to counterclockwise rotation, and vice versa, without reversing the direction of rotation of the supercharging pump and without disturbing the proper timing of the breaker mechanism or of the distributor rotor. No additional parts are required in this operation and the reversal may be made in the field if necessary. Furthermore, the reversal may be desirable even if the pump is not incorporated in the magneto. The same result in rearranging the timing of the breaker and distributor mechanisms may be obtained by providing a second properly displaced keyway in the pinion |5 or gear I6, but the proper timing is reestablished more conveniently and reliably by the arrangement herein disclosed.

Many modifications and changes may be made in the details of construction and arrangement of parts of the preferred disclosure herein described without departing from the spirit of our invention. Such features are intended to be covered by the broad terms of the appended claims.

Having thus described our invention, what we claim is:

1. In a high tension multicylinder magneto of the single spark type having a frame, a generator unit including a rotatable shaft and a stationary high tension coil arranged on-one side of the generator shaft, distributor mechanism including a rotatable cross shaft geared intermediate its ends to the generator shaft and a distributor rotor fast .on the cross shaft at the other side of the generator shaft, circuit breaker mechanism which is arranged about the. cross shaft on the same side of the shaft as the coil and which is. electrieally connected to. the coil, and a high tension cross connector extending wholly interiorly of the magneto frame from the coil and past the generator shaft to the distributor rotor..

2. Ina high tension'multicylinder magneto of the single spark type having a frame, a generator unit including a rotatable vertical shaft and a stationary high tension coil arranged on one side of the generator shaft, distributor mechanism including a rotatable horizontal cross shaft geared intermediate its ends to the generator shaft above the coil and a distributor rotor fast on the distributor shaft at the other side of the generator shaft, circuit breaker mechanism which is arranged about the distributor shaft above the coil and which is electrically connected to the coil by a vertically extending conductor, and a detachably fastened horizontally arranged high tension cross connector extending wholly interiorly of the magneto frame from the coil and past the generator shaft to the distributor rotor.

3. In a multicylinder magneto having a frame, generator mechanism including a rotatable shaft and a stationary ignition coil, distributor mechanism which includes a rotatable shaft geared to the generator shaft and a distributor electrode fast on the distributor shaft and which also includes a plurality of stationary electrodes sequentially cooperative with the distributor electrode, and a connector which extends wholly interiorly of the magneto frame from the coil and past the generator shaft to the distributor electrode and which comprises a stationary cross conductor electrically connected to the coil and a stationary conducting ring surrounding the distributor shaft in continuous electrical connection with both the distributor electrode and the conductor.

4. In a multicylinder magneto having a frame, generator mechanism including a rotatable shaft and a stationary ignition coil, distributor mechanism which includes a rotatable shaft geared to the generator shaft and a distributor electrode fast on the distributor shaft and which also includes a plurality of stationary electrodes sequentially cooperative with the distributor electrode in jump spark connection therewith, and a connector which extends wholly interiorly of the magneto frame from the coil and past the generator shaft to the distributor electrode and which comprises a stationary conductor electrically connected to the coil and a stationary conducting ring surrounding the distributor shaft in brush connection with the conductor and in jump spark connection with the distributor electrode.

5. In a multicylinder magneto having a frame, a generator mechanism including a rotatable shaft and a stationary ignition coil, distributor mechanism which includes a rotatable shaft geared to the generator shaft and a distributor electrode fast on the distributor shaft and which also includes a plurality of stationary electrodes arranged around the distributor shaft so as to be sequentially cooperative with the distributor electrode in a circle of one diameter, and a connector which extends wholly interiorly of the magneto frame from the coil and past the generator shaft to the distributor electrode and which comprises a. stationary .crosszconduotor electri! cally connected to. the coil and a stationary conductor surrounding the distributor shaftv in a circle of lesser diameter than that of the. stationary electrodes and in continuous electrical connection with both the distributor electrode and the cross conductor.

6. In a high tension magneto having a frame, generator mechanism. including a. rotatable shaft and a stationaryignition coil, distributor mechanism which includes. a rotatable shaft geared to thegeneratorshaft and a distributor electrode fasten the distributor shaft and which also includes a plurality of stationary electrodes sequentially cooperative with the distributor electrode, said ignition coil and said rotatable stationary electrodes being arranged in the generator and distributor compartments respectively, a cross connector which extends wholly interiorly of the generator compartment from the coil to the distributor electrode in electrical connection therewith, an encased supercharging pump which is detachably coupled to the distributor shaft so as to be removable therefrom as a unit and which is constructed and arranged to supercharge both of said compartments, and a separate detachable filter-carrying frame section which is detachably fastened between the supercharging pump and the end of the frame of the magneto and which together with the pump is constructed and arranged to complete the enclosure of the magneto.

'7. In a magneto, generator mechanism including a rotatable shaft, circuit breaker mechanism including a rotatable shaft having gear mounting shaft for timing the breaker shaft with respect to the generator shaft in accordance with the selected position of the gear on the breaker shaft; whereby the circuit breaker mechanism may be rotated in a single direction and in properly timed relation with the generator shaft upon rotation thereof in the selected direction.

8. In a magneto, generator mechanism including a rotatable shaft, circuit breaker mechanism including a rotatable shaft which has gear mounting seats arranged thereon on the two sides of the axis of rotation of the generator shaft and which has angularly displaced keyways for the respective seats, an angle gear fast on the generator shaft, and an angle gear on a selected one of the mounting seats thereon and keyed on the breaker shaft in mesh with the other gear; whereby the circuit breaker mechanism may be rotated in a single direction and in properly timed relation with the generator shaft upon rotation thereof in the selected direction.

9. In a high tension magneto, generator mechanism including a rotatable shaft, circuit breaker mechanism including a rotatable shaft having a gear mounting seat arranged on each of the two sides of the axis of rotation of the generator shaft, an angle gear fast on the generator shaft, an angle gear fast on a selected one of said seats on said breaker shaft in mesh with the other gear, said breaker shaft having means for timing the breaker shaft with respect to the generator shaft in accordance with the position of the gear on the breaker shaft, and a separate supercharging pump detachably coupled to the breaker shaft; whereby the circuit breaker mechanism and the supercharging pump may be operated in a single direction of rotation, and the circuit breaker mechanism operated in properly timed relation with the generator shaft upon rotation thereof in the selected direction.

10. In a high tension magneto, generator mechanism including a rotatable shaft and a bevel pinion fast on one end thereof, a rotatable cross shaft which has gear mounting seats arranged on each of the two sides of' the axis of rotation of the generator shaft and which has a bevel gear selectively keyed on one of said seats in mesh with the bevel pinion on the cross shaft, circuit breaker mechanism mounted near one end of the cross shaft, distributor mechanism mounted near the other end of the cross shaft, and a separate supercharging pump detachably coupled to the cross shaft near the circuit breaker end thereof, the cross shaft having angularly displaced keyways at each of the gear mounting seats to properly time the circuit breaker mechanism with the generator shaft up n rotation thereof in the selected di- 1 rection.

WILLIAM D. CROCKER. FRANK S. COE.

Images