US2749458A - Buchmann - Google Patents

Description

June 5, 1956 A. BUCHMANN 2,749,458

SAFETY APPARATUS FOR MAGNETOS Filed June 3, 1955 INVENTOR. H\ bm Buahmann F/G. 4 BY:

SAFETY ArrAnArus FUR MAGNETOS Albin Buchmann, Soienre, Switzerland, assignor to Scintilla Ltd, Soleure, Switzerland The present invention relates to magnetos. More particularly, the present invention relates to a safety apparatus for use with magnetos to prevent coils thereof from burning out.

One of the objects of the present invention is to provide an apparatus for automatically short circuiting a magneto coil when the speed of rotation of the magneto reaches a predetermined value.

Another object of the present invention is to provide a short circuiting apparatus of this type with a means for manually setting the same in an operating position.

A further object of the present invention is to provide a short circuiting apparatus of this type with a means for manually operating the short circuiting apparatus at will.

An additional object of the present invention is to provide a short circuiting apparatus of the above type which short circuits a coil whose circuit is closed and opened by an interrupter irrespective of the position of this interrupter.

With the above objects in view, the present invention mainly consists of a magneto having a primary coil and a housing in which a distributor arm of the magneto is turnably mounted. A centrifugal regulator or control means is provided to automatically ground the distributor arm when the speed of rotation thereof reaches a predetermined value, this control means being connected to the arm for rotation therewith and being turnable by centrifugal force to and from a grounding position where the distributor arm is grounded by the control means. A short circuit means is mounted on the housing for short circuiting the primary coil of the magneto, this short circuiting means having an actuating member for actuating the same, and this actuating member being located in the path of movement of the centrifugal control means when the latter is in its grounding position to be engaged and moved by the control means for actuating the short circuiting means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. l is a fragmentary, partly sectional and partly diagrammatic elevational view of a magneto constructed in accordance with the present invention;

Fig. 2 is a fragmentary, partly sectional view taken along line 2-2 of Fig. 1 in the direction of the arrows;

Fig. 3 is a fragmentary illustration of the structure of Fig. 2 in the short circuiting position thereof;

Fig. 4 is a fragmentary partly sectional view taken along line 4-4 of Fig. 1 in the direction of the arrows; and

2,749,458 Patented June 5, 1956 of the magneto and an interrupter and short circuiting means associated therewith.

Referring now to the drawings, Fig. 1 shows a housing 1 adapted to be mounted in a vertical position on an internal combustion engine or the like, this housing 1 of the magneto being electrically conductive so as to ground parts of the magneto, as described below. A rotor shaft 2 is turnably mounted on the housing 1 and is adapted to be rotated in a known way from the crank shaft of the internal combusion engine. A cam 3 is connected to the shaft 2 for rotation therewith and forms a part of an interrupter for opening and closing an interrupter switch of the primary coil of the magneto. A carrier 4 of electrical insulating material also is connected to the shaft 2 for rotation therewith and carries an electrically conductive distributor arm 5 from which current jumps in a known way to the several electrodes 10 located in distributor head 11 during rotation of carrier 4 and arm 5 so as to cause fuel-air mixtures in the cylinders of the engine to be ignited in a predetermined sequence, as is Well known.

A support 12 is grounded to the housing 1 through the cam 3 and carries an electrically conductive pivot pin 7 on which a centrifugal regulator or control member 6 is turnably mounted, this support 12 being located between members 3 and 4 and connected to the former for rotation therewith during rotation of shaft 2. The centrifugal control member 6 is a centrifugal control means for limiting the speed of rotation of the engine, this control member 6 being electrically conductive and grounded through members 7, 12, 3, and 1. The control member 6 includes a pair of bell cranks formed by a pair of long stirrup-formed arms 6' and a pair of shorter arms 6" respectively joined to arms 6', the arms 6" carrying between themselves a weight 8 and a spring 9 being connected to the weight 3 and a part of support 12 spaced from pivot pin 7 (Fig. 4) to urge the control member 6 to the solid line position shown in Fig. 1. A part of the front arm 6" of Fig. 1 is broken away to show the spring 9 and weight 8.

As the speed of rotation of the engine increases, the speed of rotation of shaft 2 also increases, as is Well known, and by centrifugal force the weight 8 and the control member 6 turn against the action of spring 9 in a clockwise direction about pin 7, as viewed in Fig. 1, so that the control member 6 becomes located in the dotted line position shown in Fig. 1 where the free end of the control member joining arms 6' closely approaches the arm 5 to cause current to jump from the latter to the control member 6 to be grounded thereby so as to stop operation of the engine and thereby limit the speed of rotation thereof. The control member 6 includes at its right hand side, as viewed in Fig. 1, a horizontal extension Fig. 5 is a. fragmentary wiring diagram showing a coil extending between arms 6 and provided with a downwardly extending lug 6" for a purpose to be described below.

The wall portion of the housing 1 is formed with an opening passing therethrough, as is shown at the lower right hand side of Fig. 1, and an electrically conductive member 13 is provided with a tubular bearing portion extending through this opening and having an outer threaded surface located at the exterior of housing 1 and engaged by a nut 14 on the outside of housing 1 for fixing member 13 thereon, as is shown in Fig. 1. As is apparent from Fig. 2, the member 13 is formed in the interior of housing 1 with a notch in which an electrically conductive switch member 16 is located, this switch member forming almost a complete circle and being fixed to a shaft 15 which extends through the tubular bearing portion of member 13 to be turnably carried there by, a handle 17 of electrical insulating material being fixed to the shaft 15 on the outside of housing 1. Shaft 15 may be made of electrical insulating material, if dcsired. A switch operating member 18 is fixed to the switch member 16 and extends upwardly therefrom as shown in Fig. 2. In the interior of housing 1, the member 13 is formed with a recess in which a block 19 of electrical insulating material is located, this block 19 carrying a springy switch member 2t? which is connected by the lead 21 to the primary coil 22 of the magneto (Fig. and the free end of switch member 24) hearing against an insulated part 13' of member 13, when the parts are in the positions shown in Fig. 2.

Fig. 5 diagrammatically shows the primary coil 22 of the magneto and the interrupter switch 23 electrically connected thereto for opening and closing the circuit thereof, this switch 23 being engaged by the interrupter cam 3 which opens the switch 23 a ainst the action of spring 24. As is shown in Fig. 5, the lead 21 is connected to the primary coil 2?. and the sv'itch member 29 for short circuiting the primary coil 22 when switch member 2i) is grounded by contact with member 16. As is apparent from Fig. 5, interrupter 23 is bridged by line zll and. switch 16, 20 so that when this latter switch is closed the coil 22 will be short circuited irrespective of the position of the interrupter.

The above-described apparatus operates as follows:

As the speed of rotation of the engine increases, the arms 6" approach arm 5 to eventually ground the latter when the speed of rotation of the engine and arm 5 reaches a predetermined value, as was described above. The turning of the centrifugal control member 6 causes the lug 6' to become lowered until it is located at the elevation of switch operating member 18, as shown in dotdash lines in Fig. 2, and at this time, when the regulator 6 is in its grounding position for grounding arm 5, the turning lug 6", which moves in the direction of the arrow shown at the top of Fig. 2, will engage switch operating member 18 to turn the latter and switch member 16, shaft and handle 17 therewith to the position shown Fig. 3 where the switch operating member 18 engages an inclined face of member 13. in this position, switch member 16 engages switch member 2b to close the switch 16, 20, and the lead 21 connected to the primary coil 22 is grounded through the switch members and 16, member 13 and housing ll, so that the primary coil 22 cannot become burnt out. The grounding of arm 5 by the control member 6 short circuits the secondary coil of the magnetosince one end of the secondary coil is already grounded. The effective result is a Zero load to the primary coil and an increased current flow through the primary coil will take place which might cause the primarycoil to be burned out if it were not automatically short circuited by the apparatus of the invention.

To reset the apparatus it is only necessary to turn the handle 17 so as to rotate shaft 15 and switch member 16 therewith to again locate the parts in the position shown Fig. It should be noted that the handle 17 not only serves to reset the apparatus. This handle also may be used to short circuit the primary coil 22 at will so that the engine may be stopped at any time in this way.

I It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of ma netos differing from the types described above.

While the invention has been illustrated and described as embodied in safety apparatus for magnetos, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a magneto having a primary coil, in combination, a housing; a distributor arm turnably mounted in said housing; centrifugal control means for automatically grounding said distributor arm when the speed of rotation thereof reaches a predetermined value; and short circuiting means mounted on said housing for short circuiting the primary coil of the magneto, said short circuiting means being located adjacent said centrifugal control means to be actuated thereby for short circuiting the primary coil when said control means grounds said distributor arm.

2. In a magneto having a primary coil, in combination, a housing; a distributor arm turnably mounted in said housing; centrifugal control means for automatically grounding said distributor arm when the speed of rotation thereof reaches a predetermined value, said control means being connected to said arm for rotation therewith and being turnable by centrifugal force to and from a grounding position where said arm is grounded by said control means; and short circuiting means mounted on said housing for short circuiting the primary coil of the magneto, said short circuiting means having an actuating member for actuating the same and said actuating member being located in the path of movement of said centrifugal control means when the latter is in said grounding position thereof to be engaged and moved by said control means for actuating said short circuiting means.

I 3. In a magneto having a primary coil, in combination, a housing; a distributor arm turnably mounted in said housing; centrifugal control means for automatically grounding said distributor arm when the speed of rotation thereof reaches a predetermined value, said control means being connected to said arm for rotation therewith and being turnable by centrifugal force to and from a grounding position where said arm is grounded by said control means; short circuiting means mounted on said housing for short circuiting the primary coil of the magneto, said short circuiting means having an actuating member for actuating the same and said actuating member being located in the path of movement of said centrifugal control means when the latter is in said grounding position thereof to be engaged and moved by said control means for actuating said short circuiting means; and manually operable setting means operatively connected to said short circuiting means for setting the latter in a position Where the primary coil is not short circuited.

4. In a magneto having a primary coil, in combination, a housing; a distributor arm turnably mounted in said housing; centrifugal control means for automatically grounding said distributor arm when the speed of rotation thereof reaches a predetermined value, said control means being connected to said arm for rotation therewith and being turnable by centrifugal force an and from a'grounding position where said arm is grounded by said control means; and switch means adapted to be connected to the primary coil of the magneto for short circuiting the same when said switch means is in the closed position thereof, said switch means having a switch operating member located in the path of movement of said centrifugal control means when the latter is in said grounding position thereof to be engaged and moved by said control means to close said switch means for short circuiting the primary coil.

5. In a magneto having a primary coil, in combination, a housing; a distributor arm turnably mounted in said housing; centrifugal control means for automatically 7 grounding said distributor arm when the speed of rotation thereof reaches a predetermined value, said control means beingeonnected to said arm for rotation therewith and being turnable by centrifugal force to and from a grounding position where said arm is grounded by said control means; switch means adapted to be connected to the primary coil of the magneto for short circuiting the same when said switch means is in the closed position thereof, said switch means having a switch operating member located in the path of movement of said centrifugal control means when the latter is in said grounding position thereof to be engaged and moved by said control means to close said switch means for short circuiting the primary coil; and manually operable means operatively connected to said switch means for setting the same in the open position thereof.

6. In a magneto, in combination, a primary coil; an electrically conductive housing for grounding parts of the magneto; a distributor arm insulated from said housing and being turnably mounted therein; an electrically conductive centrifugal control member insulated from said arm and being connected thereto for rotation therewith, said control member being electrically connected to said housing and being turnable to and from a grounding position adjacent said arm for grounding the latter when the speed of rotation of said arm reaches a predetermined value; and a short circuiting switch connected to said primary coil for short circuiting the latter when said switch is closed, said switch including a switch member carried by said housing and being electrically connected thereto for grounding the primary coil when said switch is closed, and a switch operating member connected to said switch member and located in the path of movement of said control member when the latter is in said grounding position thereof to be engaged and moved by said control member for closing said switch to short circuit said primary coil.

7. In a magneto, in combination, a primary coil; an electrically conductive housing for grounding parts of the magneto; a distributor arm insulated from said housing and being turnably mounted therein; an electrically conductive centrifugal control member insulated from said arm and being connected thereto for rotation therewith, said control member being electrically connected to said housing and being turnable to and from a grounding position adjacent said arm for grounding the latter when the speed of rotation of said arm reaches a predetermined value; an interrupter electrically connected to the primary coil for opening and closing the circuit thereof; and a short circuiting switch bridging said interrupter and being electrically connected to said primary coil for short circuiting the latter irrespective of the position of said interrupter, when said switch is closed, said switch including a switch member carried by said housing and being electrically connected thereto for grounding the primary coil when said switch is closed, and a switch operating member connected to said switch member and located in the path of movement of said control member when the latter is in said grounding position thereof to be engaged and moved by said control member for closing said switch to short circuit said primary coil.

8. In a magneto, in combination, a primary coil; an electrically conductive housing for grounding parts of the magneto, said housing having a wall portion formed with an opening passing therethrough; a distributor arm insulated from said housing and being turnably mounted therein; an electrically conductive centrifugal control member insulated from said arm and being connected thereto for rotation therewith, said control member being electrically connected to said housing and being turnable to and from a grounding position adjacent said arm for grounding the latter when the speed of rotation of said arm reaches a predetermined value; an electrically conductive tubular bearing member fixed to said housing and extending through said opening thereof; a first switch member insulated from said bearing member and being carried thereby in the interior of said housing, said first switch member being electrically connected to the primary coil; a shaft extending through said tubular hearing member and being turnably supported thereby; and a second switch member electrically connected to said bearing member to be grounded by contact between the latter and said housing, said second switch member being located opposite said first switch member and being fixed to said shaft for turning movement therewith to and from a position engaging said first switch member for grounding the primary coil; and a switch operating member fixed to said second switch member and being located in the path of movement of said control member when the latter is in said grounding position thereof to be engaged and moved thereby for turning said second switch member and said shaft therewith to a position where said second switch member engages said first switch member.

9. In a magneto, in combination, a primary coil; an electrically conductive housing for grounding parts of the magneto, said housing having a wall portion formed with an opening passing therethrough; a distributor arm insulated from said housing and being turnably mounted therein; an electrically conductive centrifugal control member insulated from said arm and being connected thereto for rotation therewith, said control member being electrically connected to said housing and being turnable to and from a grounding position adjacent said arm for grounding the latter When the speed of rotation of said arm reaches a predetermined value; an electrically conductive tubular bearing member fixed to said housing and extending through said opening thereof; a first switch member insulated from said bearing member and being carried thereby in the interior of said housing, said first switch member being electrically connected to the primary coil; a shaft extending through said tubular bearing member and being turnably supported thereby; and a second switch member electrically connected to said bearing member to be grounded by contact between the latter and said housing, said second switch member being located opposite said first switch member and being fixed to said shaft for turning movement therewith to and from a position engaging said first switch member for grounding the primary coil; a switch operating member fixed to said second switch member and being located in the path of movement of said control member when the latter is in said grounding position thereof to be engaged and moved thereby for turning said second switch member and said shaft therewith to a position where said second switch member engages said first switch member; and a handle located outside of said housing and being fixed to said shaft for turning the latter so that the primary coil may be grounded at will by turning said handle and so that said second switch member may be manually turned away from said first switch member by said handle.

10. In a magneto, in combination, a primary coil; an electrically conductive housing for grounding parts of the magneto, said housing having a wall portion formed with an opening passing therethrough; a distributor arm insulated from said housing and being turnably mounted therein; an electrically conductive centrifugal control member insulated from said arm and being connected thereto for rotation therewith, said control member being electrically connected to said housing and being turnable to and from a grounding position adjacent said arm for grounding the latter when the speed of rotation of said arm reaches a predetermined value; an electrically conductive tubular bearing member fixed to said housing and extending through said opening thereof; a first switch member insulated from said bearing member and being carried thereby in the interior of said housing, said first switch member being electrically connected to the primary coil; a shaft extending through said tubular bearing member and being turnably supported thereby; and a second switch member electrically connected to said bearing member to be grounded by contact between the latter 7 ri'r'l-sziid housihg'; s'fiid' Second switch member being 10'- eated ofiposite said first switch member and being fixed to said shift for t'u'rnihg movement therewith to and fr'crn '2' position engaging said first switch member for grounding the primary coil; a switch ope'ra'ting member fixed to said second switch member and being located in the path of ifioveinent of 'saidcontrol member when he latter' is in said grounding position thereof to be engaged'and moved thereby for turning said second switch member and said shaft therewith to a position where said second switch member engages said first switch member; and a handle located outside of said housing afid being fixed to said 'shziftfor fiirning the latter so References Cited in the file of this patent UNITED STATES PATENTS 1,319,256 Van Deventer Oct. 21 1919 1,502,594 Spiv a July 22, 19 24 1,925,883 Smith Sept. 5, 1933 2,324,169 Moran July 13, 1943

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