US2978550A - wischhusen - Google Patents

Description

April 4, 1961 E. H. WISCHHUSEN IGNITION APPARATUS 2 Sheets-Sheet 1 Filed July 24, 1956 INVENTOR. Egon H.Wischhusen BY 6% $W AT ORNEY April 4, 1961 E WISCHHUSEN 2,978,550

IGNITION APPARATUS Filed July 24, 1956 2 Sheets-Sheet 2 57 59 1s FIG.2

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Egon H.Wischhusen 52 ATTORNEY United States Patent IGNITION APPARATUS Egon H. Wischhusen, Sidney, N.Y., assignor to The Bendix Corporation, a corporation of Delaware Filed July 24, 1956, Ser. No. 599,861

11 Claims. (Cl. 200-20) This invention relates to an improved magneto or ganization. The magneto of the invention is particularly useful in the ignition system of an internal combustion engine.

In its preferred embodiment illustrated herein the magneto of the invention is made as a unit adapted to be attached to an internal'combustion engine, the magneto having a shaft driven by the engine in synchronism therewith. The magneto includes a low tension generator having a rotor mounted on the shaft, a distributor driven by the shaft, and a high tension coil. The distributor comprises a set of low tension breaker points periodically opened and closed by a cam on the shaft to make and break the circuit to the primary of the coil. The output from the secondary of the coil is fed to the high tension switching portion of the distributor, whereby high tension electrical impulses are fed in timed relation to the spark plugs ofthe engine.

The high tension switching portion of the distributor of conventional magnetos is usually made as a one-piece removable cap on the magneto housing. Such cap is conventionally made of molded insulating material, and contains a central terminal and angularly spaced branch terminals as inserts molded in the cap. This type of cap is comparatively expensive to make, since the molding operation, involving the placing of inserts, is relatively slow. In conventional construction, if one terminal of the cap becomes faulty, a whole new cap must be sup plied since the terminals are not removable. Further, such molded cap construction is not very resistant to mechanical shocks and blows, so that sometimes the cap becomes cracked and broken.

In the usual prior distributor the cam operating the low tension breaker is connected to the main shaft of the distributor by a key. Such construction, to be satisfactory, requires close tolerances in the machining of the shaft, the cam, and of the key means attaching the cam to the shaft, since unless the cam fits tightly, and is held in accurately angularly oriented position on the shaft, the timing of the discharges from the distributor to the spark plugs will be inaccurate.

The present invention provides a magneto having an improved distributor assembly which is characterized by its ruggedness and also by its economy and ease of manufacture and assembly. In the preferred embodiment of the distributor of the invention shown and described herein, the housing of the distributor and the distributor cap are of metal, and the brush assembly on the cap, cooperating with a rotating high tension current-distributing finger, comprises a separate support made of insulating material and attached to the housing of the cap. The branch high tension terminals, which are angularly disposed around the central terminal of the distributor, are made separate from each other and from the central terminal, and are detachably secured to the outer housing portion of the cap.

The cable leading from the high tension coil of the magneto to the brush assembly of the central terminal Fatented Apr. 4, 1961 of the distributor is attached to such assembly by a novel solderless slip connection, which is quickly and economically made. The configurations and the relative dispositions of the terminal on the coil and the central brush assembly are such that the cable is stably retained in the central brush assembly when the cap of the distributor is assembled on the main body of the distributor. The brush assembly includes a removable electrically conducting insert mounted in the insulating support. The lead cable and the electrically conducting insert of the brush assembly are so disposed relative to each other that the cable retains the insert in place in. the insulating support without the necessity of any other attaching means for such insert.

The distributor of the illustrative embodiment further includes a novel, simple and inexpensive means for at-' taching the distributor cam to the shaft of the distributor. The attaching means of the invention is of such construction that a high precision in the machining of the means retaining the cam at the desired angle on the shaft is not necessary, the cam is easily assembled upon; or disassembled from the shaft, and the cam attaching means always retains the cam tightly and accurately located in the desired angular position upon the shaft throughout the life of the distributor.

The invention has among its objects the provision of an improved magneto organization, including a simplified and economical distributor assembly.

Another object of the invention resides in the provision of an improved end cap and brush assembly for the central terminal of a distributor of the type indi' cated.

Yet another object of the invention lies in the provision of a simplified means for attaching a cable from a high tension current source to the central brush assembly of the distributor, and the provision of such attaching means which also serves to retain a central electrically conducting insert of the brush assembly in position in the insulating support therefor.

The above and further objects of the invention relating to economics of construction and operation of the magneto of the invention will be more readily apparent from consideration of the following specification, and of the accompanying drawings forming a part thereof, which describe and illustrate a preferred embodiment of the distributor.

In the drawings:

Figure 1 (Sheet 1) is a fragmentary view on an enlarged scale and generally in longitudinal axial section of the distributor portion of an illustrative embodiment of a magneto, certain of the parts being shown in side elevation.

Figure 2 (Sheet 2) is a view in end elevation of such unit from the cap end of the distributor, an upper portion of such cap being broken away to show the low tension breaker assembly of the distributor.

Fig. 3 (Sheet 2) is a view in transverse section through the cap end of the distributor, the section being taken along the line 33 of Figure 1.

Figure 4 (Sheet 1) is a fragmentary view in section on an enlarged scale of a portion of the housing of the cap and the insulating base portion of the insert supporting the central terminal assembly of the insert.

Figure 5 (Sheet 2) is an enlarged fragmentary view in axial cross section through the main shaft of the distributor in the location of the cam mounted on such shaft.

Figure 6 (Sheet 1) is an exploded view in perspective of a fragment of the main shaft of the distributor, the

cam for operating the low tension breaker assembly of the distributor, and the resilient sleeve-like pin for attaching the cam to the shaft.

In Figure 1 there is shown a magneto unit which includes a generator it contained in the left-hand end (as it is shown in Figure 1) of body portion 11 of the housing of the unit, and a distributor contained inthe righthand end of such unit. A cap 12, attached to the body ii. of the housing by screws 14 (Fig. 2), covers the distributor. Preferably both the housings of the body 11 and of the cap 12 are made of metal such as steel.

The magneto unit has a main longitudinally extending drive shaft 15 adapted to be rotated in synchronism with an. internal combustion engine (not shown) to which it is drivingly connected. Shaft 15 carries the rotor of the generator of the magneto, and also has non-rotatably connected thereto a cam 16 for operating a low tension breaker assembly 17 of the distributor. The right-hand end of shaft 15, as it is shown in Figure 1, extends through journal 19 of the magneto unit and carries an insulating distributor rotor body 20, which is keyed thereto by means generally indicated at 21. Rotor body carries an L-shaped distributor finger 22 thereon, such finger having a radially disposed portion and a terminal portion 26 disposed at right angles thereto and parallel to the axis of shaft 15. Equally spaced angularly about the cap of the magneto unit, in position to cooperate with portion 26 of the distributor finger, is a plurality of high tension terminals 24 having points 25. Eight such terminals are shown in the disclosed embodiment, since the magneto unit is designed to supply the ignition needs of anti-cylinder engine. A central brush assembly, gen erally designated 27, supported axially of the cap constantly makes contact with distributor finger 22v thereby to distribute high tension current from coil 29 mounted within the magneto housing to the distributor finger.

' it will be appreciated from the above that the generator of the magneto generates low tension electric current which is led, by wires not shown, to the low tension breaker assembly 17. The cam 16 which has 8 lobes, opens'the contacts of the low tension breaker assembly at the required time, so that the low tension current fed to the primary of high tension coil 29 is interrupted. The resulting changes in the flux 0f the coil causes high tension impulses to be generated in the secondary of the coil. Such impulses are led through cable 32 to the central brush assembly 27. At each such impulse, part 26 of the distributor finger 22 confronts the appropriate contact point of a high tension terminal 24, so that the spark plugs (not shown) which are connected to such terminals discharge in sequence.

The novel central brush assembly, the supporting plate therefor secured to the cap of the distributor, and the improved means for connecting such cable to the central brush assembly will now be described. As shown in Fig: ures l and 2, the outer end portion 13 of the housing 12 of the distributor cap has on its inner surface a central circular recess or seat 35 having a flat bottom. Within such seat there is positioned the circular base plate portion 3-7 of an insulating, central brush assembly supporting member 36. Plate portion 37 has a diameter slightly A smaller than the diameter of recess 35, and a thickness approximating the depth of such recess. The rear surface 38 (Figs. 1 and 4) of plate portion 37 and the bottom surface of seat 35 may be roughened as by being grit blasted. A layer 39 of cement between surface 38 and the bottom of the seat 35 holds insulating support 36 securely in place on the housing 12 of the cap.

' As shown in Figures 1 and 3, insulating support 36 is provided with an inwardly extending integral boss 40 which is centrally positioned on member 36 with respect to a vertical axial plane (Fig, 1) therethrough, and which extends a somewhat greater distance below the axis of the cap than above it. Boss 40 has molded therein an axially extending blind passage 41, which is square in transverse section and which is open inwardly of the distributor cap. A round blind passage 42, having its axis lying on the vertical axial plane through the shaft 15, extends parallel to the main extent of plate portion 37 and at right angles to the axis of shaft 15. Hole 42, which may be drilled in boss 44], has a diameter somewhat less than the length of the sides of the square passage 41, and as shown in Figure 3, lies normal to one of the sides of passage 41. Preferably, as shown, passage 42 extends inwardly of square passage 41 in boss 40 for an appreciable distance. 7

A brush-holding insert 44, which is square in cross section, fits accurately and slidingly in passage 41. Insert 44, which is made of metal such as brass, carries on its inner end a carbon brush 45, which is retained in a central recess in the end of the insert 44 by a flange 46 surrounding the recess on the insert and rolled over the periphery of the carbon brush. Distributor finger 22 carries centrally thereof a contact 47 which is constantly urged into engagement with carbon brush by means of a spring arm 49 which connects the contact with the finger, as shown.

Insert number 44 has a hole 5t} therethrough, hole 50 being of approximately the same diameter as hole 42 in member 36and being aligned with hole 42 when the insert is fully inserted in member 36. As mostclearly shown in Figure 1, cable 32 from coil 29 to the central brush assembly makes contact with insert 44 at the hole 50 through the latter. Cable 32 has a resilient rubber or rubber-like sheath 52 thereon. At the end of cable 32 which is to make contact with the central brush assembly, the insulation is removed therefrom for a length which is somewhat less than the depth of the hole 42 in member 36. The thus exposed stranded wires 51 are then bent generally 180 so that they lie closely alongside the insulating sheath at the upper end of the cable 32. When thus disposed, such stranded wires form a generally ferrule-like configuration on the upper end of the cable 32. The relaxed diameter of such ferrulelike configuration on the cable somewhat exceeds the diameter of the holes 42 and it], so that when the thus treated cable end is thrust into holes 42 and 50 it engages them quite firmly and makes a good electrical contact with insert 44.

As shown in Figure 1, the coil 29 has a terminal socket 30 thereon, such terminal socket being contained in an elongated insulating sleeve 31 connected with the housing for the coil. The lower left-hand end of cable 32 has a terminal 34 thereon which is resiliently received in socket 3%. Terminal socket 3t? 01' the coil extends in a direction at right angles to the hole 42 in member 36. When the cap 12 of the distributor is operatively mounted on the magneto, the ferrule-like configuration formed by wires 51 on the upper (Fig. 1 end of cable 32 is fully engaged in holes 42 and 50, with the ferrulelike configuration extending in passage 42 through and beyond insert 44, and the terminal 34 on the bottom lefthand end ofthe cable is fully engaged in socket 36 on the coil. I

v In assembling the distributor, the upper ferrule-like end of cable 32 is first fully inserted into holes 42 and 50 of the insulating support and conducting insert of the cap, respectively, as described. The lower terminal 34 on cable 32 is then inserted into the outer .end of insulating sleeve 31 on the housing of the coil. Cable 32 is relatively short and fairly stiff, so that, when the distributor cap is advanced into fully assembled position on the magneto, terminal 34 on the cable 32 enters socket 30 and advances into fully inserted position therein. At the start of such assembling operation the inner lower curved wall of the housing 12 of the cap may assist in thrusting the lower end of cable 32 to the left. When ,cap 12 of the magneto is disassembled, a simple axial pull of the central brush assembly. The upper end of such cable also retains insert 44 in member 36 without the necessity of providing any other means for attaching the insert to insulating support 36, since the ferrule-like configuration on cable 32 functions as a retaining pin or key for insert 44.

The means for attaching the cam 16 to shaft 15 is accurately oriented angular position thereon is shown more clearly in Figures 5 and 6. A blind hole 54 is located radially of shaft 15 at the correct position longitudinally thereof. A resilient stifi split pin-like sleeve member 55, having a relaxed diameter somewhat greater than that of the hole 54, is pressed into such hole with the slot 56 in the sleeve facing axially outwardly of the shaft toward the cap of the distributor. Both ends of the sleeve are beveled at 57, to aid in insertion of the sleeve regardless of which end is placed in hole 54. Cam 16 has a sleeve portion 60 of reduced diameter at one end thereof, such sleeve portion having an axially extending slot 59 therein adaptedresiliently to receive the outer end of sleeve 55 after the latter has been inserted in hole 54.

The radially inner ends of the sides of the split sleeve 55 constantly resiliently engage the walls of hole 54 in shaft 15, and the radially outer ends of the sides of the split sleeve constantly resiliently engage the sides of slot 59 in portion 60 of cam 16. As a result, the cam is securely held on the shaft against rotation with respect to the shaft and also against fortuitous movement axially of the shaft. The cam may, however, be easily assembled on the shaft or disassembled from it by a tool engaging the cam and thrusting it in the proper direction axially of the shaft.

In a typical satisfactory distributor made in accordance with the present invention, hole 54 in shaft 15 has a diameter of .125, |.002, -.000 inch, slot 59 has a width equal to such diameter, and split sleeve 55, which is made of carbon steel S.A.E. 1095, has a relaxed diameter of .135 inch.

Although for purposes of illustration a preferred embodiment of the magneto of the invention has been shown and described, it will be understood that such embodiment is illustrative only since the distributor is capable of considerable variation as to details. The invention is, therefore, to be defined by the claims appended hereto.

I claim:

1. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft, the housing having a removable cap overlying the rotor, the improvement which comprises a central terminal including a brush assembly making contact with the rotor and cooperating successively with the branch terminals, said central terminal including a broad electrically insulating support disposed generally normal to the shaft and overlying the rotor thereon, the support being cemented to the inner face of the cap, the support having a recess with sidewalls therein aligned with and open inwardly toward the shaft, an electrically conducting insert slidably mounted in and directly engaging the sidewalls of the recess in the support, and means retaining the insert against withdrawal axially inwardly of the cap.

2. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft, the housing having a removable cap overlying the rotor, the improvement which comprises a central terminal including a brush assembly making contact with the rotor and cooperating successively with the branch terminals, said central terminal including a broad electrically insulating support disposed generally normal to the shaft and overlying the rotor thereon, a central seat on the interior of the cap receiving the support, the sup port being cemented in the seat in the cap, the support having a recess with sidewalls therein aligned with and open inwardly toward the shaft, an electrically conducting insert slidably mounted in and directly engaging the sidewalls of the recess in the support, and means retaining the insert against withdrawal axially inwardly of the cap.

3. In electrical apparatus having an electrically insulating support and an electrically conducting insert slidably mounted in an open ended recess in the support, the improved means for retaining the insert against withdrawal from the support and for making electrical connection with the insert, which comprises a generally transverse passage in the insert and through one side of the support, and a cable extending into the transverse passage, said cable having a core slidably received within the insert and making electrical connection therewith.

4. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft and cooperating with the rotor, the housing having a removable cap overlying the rotor, a central terminal on the cap, said central terminal including a brush assembly making contact with the rotor, the improved central terminal organization which includes an electrically insulating support on the cap disposed generally normal to the shaft and overlying the rotor, the support having an inwardly open recess therein aligned with the shaft, an electrically conducting insert slidably mounted in the recess in the support, and means retaining the insert against withdrawal axially inwardly of the cap,

said last named means comprising a passage disposed generally transverse to the insert and extending through one side of the support and into the insert, and a cable extending through the passage in the support and into the insert and making electrical connection with the insert.

5. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft and cooperating with the rotor, the housing having a removable cap overlying the rotor, and a central terminal on the cap, said central terminal including a brush assembly making contact with the rotor, the improved central terminal organization which includes an electrically insulating support on the cap disposed generally normal to the shaft and overlying the rotor, the support having an inwardly open recess therein aligned with the shaft, an electrically conducting insert slidably mounted in the recess in the support, and means retaining the insert against withdrawal axially inwardly or" the cap, said last named means comprising a passage disposed generally transverse to the insert and extending through one side of the support and into the insert, and a cable having an insulating sheath extending through and substantially engaging the wall of the passage in the support, the inner end of the cable extending into the insert and making electrical connection with the insert.

6. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft and cooperating with the rotor, the housing having a removable cap overlying the rotor, and a central terminal on the cap, said central terminal including a brush assembly making contact with the rotor,

the improved central terminal organization which in- I: eludes an electrically insulating support on 'thecap disposed generally normal to the shaft and overlying the rotor, the support having an inwardly openrecess therein aligned with the shaft, an electrically conducting insert mounted in the recess in the support, and means retaining the insert against withdrawal axially inwardly of the cap, said last named means comprising a passage disposed generally transverse to the insert and extending through one side of the support and into the insert, and a cable having acore and an insulating sheath, the cable extending through and fairly snugly fitting within the passage in the support, the sheath being removed from the inner end of the cable to expose the core, the inner end of the cable core extending Within the passage in the insert and making electrical connection with the insert.

7. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft and cooperating with the rotor, the housing having a removable cap overlying the rotor, and a central terminal on the cap, said central terminal including a brush assembly making contact with the rotor, the improved central terminal organization which includes an electrically insulating support on the cap disposed generally normal to the shaft and overlying the rotor, the support having a recess therein aligned with the shaft, an electrically conducting insert mounted in the recess in the support, and means retaining the insert against withdrawal axially inwardly of the cap, said last named means comprising a passage disposed generally transverse to the insert and extending through one side of the support and into the insert, and a cable extending into the transverse passage and within the insert and making electrical con nection with the insert, the cable having a stranded wire core and a resilient insulating sheath, the sheath being removed at the end of the cable and the wire core at such end being bent back along the sheath, the resulting cable core and sheath formation at the end of the cable having a relaxed diameter somewhat exceeding the diameter of the passage in the insert, the formation lying within the passage in the insert with the exposed cable core making forcible contact therewith.

8. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft and cooperating with the rotor, the housing having a removable cap overlying the rotor, and a cent al terminal on the cap, said central terminal including a brush assembly making contact with the rotor, the improved central terminal organization which includes an electrically insulating support disposed generally normal to the shaft and overlying the rotor, the support having a recess therein aligned with the shaft, an electrically conducting insert mounted in the recess in the support, and means retaining the insert against withdrawal axially inwardly of the cap, said last named means comprising a passage disposed generally transverse to the insert and extending through one side of the support and into the insert, and a cable extending into the transverse passage and within the insert and making electrical connection with the insert, the cable having a stranded wire core and a resilient insulating sheath, the sheath being removed at the end of the cable and the Wire core at such end being unstranded and bent back along the sheath in a ferrule-like formation, the resulting ferrule-like formation having a relaxed diameter somewhat exceeding the diameter of the passage in the insert, the ferrule-like formation lying within the passage in the insert and making forcible contact therewith, the sheath having a diameter such that it fairly snugly fits within the passage through one side of the support.

"9. In electrical apparatus having a support, thesupport having a portion thereof removable from the main portion of the support in a direction'axially of the support, the improvement which comprises a first terminal including an velectrically insulating member on the removable portion of the support, an inwardly open recess in the insulating member, an electrically conducting insert slidably mounted in the recess in the insulating member, a transverse passage through one side of the insulating member extending into the insert and intersecting the recess in the insulating member, a second terminal on the support, said second terminal being located near the insert and having a cable-receiving passage lying generally at a marked angle to the passage in the insulating mom er and the insert and adjacent the open end of such latter passage, and a short stiff flexible cable having its ends extending into and slidably received within the passage in the second'terminal and the passage in the insulating member and insert, the end of the cable making electrical contact with the second terminal and the insert, the cable being of such length that when the removable portion of the support is in operative position the cable is under at least slight compression.

10. In electrical apparatus having a support, the support having a portion thereof removable from the main portion of the support in a direction axially of the'support, the improvement which comprises a first terminal including an electrically insulating member on the removable portion of the support, an inwardly open recess in the insulating member, an electrically conducting insert slidably mounted in the recess in the insulating member, a transverse passage through one side of the insulating member extending into the insert and intersecting the recess in the insulating member, a second terminal on the support, said second terminal being located near the insert and having a cable-receiving passage lying generally at a right angle to the passage in theinsulating member and the insert and adjacent the open end of such latter passage, and a short stiff flexible cable having its ends extending into and slidably received within the passage in the second terminal and the passage in the insulating member and insert, the ends of the cable making electrical contact with the second terminal and the insert, the intermediate portion of the cable lying in an arc subtending an angle on the order of the cable being of such length that when the removable portion of the support is in operative position the cable is under at least slight compression.

11. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in vsynchronism with the engine, a rotor mounted on the shaft, a plurality of branch terminals angularly spaced about the shaft and cooperating with the rotor, the housing having a cap overlying the rotor and removable from the main portion of the housing in a direction axially of the shaft, the improvement which comprises a central terminal on the cap including a brush assembly making contact with thefrotor, said central terminal including a central electrically insulating support on the interior of the cap, an inwardly open recess in the support aligned with the shaft, an electrically conducting insert slidably mounted in, the recess in the support, a transverse passage through one side of the support and into the insert, a high tension terminal within the housing supplied with timed high tension impulses by the distributor, said high tension terminal being located near the insert and having a cablereceiving passage lying generally at a right'angle to the passage in the support and the insert and adjacent the open end of such latter passage, and a short stiff flexible cable having its ends extending into and slidably received within the passage in the high tension terminal and the passage in the support and the insert, the ends of the cable making electrical'c'on'tact with the high tension terminal and the insert, the cable being of such length that when the cap 9 is in operative position the cable is under at least slight 1,935,610 compression. 2,024,896 2,143,110 References Cited in the file of this patent 2,169,595 2,413,743 UNITED STATES PATENTS 2,418,504 1,479,583 Carey Jan. 1, 1924 2 44 54 1,532,591 Krokavetz Apr. 7, 1925 2,525 130 1,721,720 Thomas July 23, 1929 2,574,698 1,736,861 Paquit Nov. 26, 1929 10 2,757,273

10 Beeh et a1. Nov. 21, 1933 Tillson Dec. 17, 1935 Hartzell Jan. 10, 1939 Sherman Aug. 15, 1939 Carlson Ian. 7, 1947 Frei Apr. 8, 1947 Purdy Sept. 7, 1948 Purdy et a1. Oct. 10, 1950 Hall Nov. 13, 1951 Taylor July 13, 1956

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