US2769046A - Breaker point apparatus - Google Patents

Description

Oct. 30, 1956 A. c. RUSSELL BREAKER POINT APPARATUS Filed Jan. 17, 1955 HTTONE United States Patent @ffice 2,769,046 BREAKER POlN'i APPARATUS Andrew Craig Russen, Shawnee,

This invention relates to internal combustion engines and, more specifically, to breaker point apparatus for use in the distributor mechanisms conventionally forming a part of such engines. The apparatus contemplated by this invention moreover constitutes a further improvement over the breaker point assembly disclosed in my copending application Serial No. 455,483, tiled September i3, 1954.

Although the breaker point assembly disclosed in my aforesaid copending application is possessed of many advantages over the types of breaker points theretofore conventionally employed, particularly with respect to decreasing the electrical resistance of, and therefore increasing the amount of electrical :current now through, the breaker point assembly during the makes thereof and with respect to effecting increased dwell time of the contacts during make periods of the breaker point assembly, it has been found that still further advantageous features may be incorporated in appara-tus of this general class. Such features include the further increasing of current liow, the further improvement of dwell time control and the further minimization of wear upon the electrical contacts forming a part of the apparatus.

Accordingly, it is the primary object of this invention to provide breaker point apparatus having such additional, advantageous features.

lt is another important object of this inven-tion to provide breaker point apparatus utilizing a single set of electrical contacts comprising, in essence, opposed plates of considerable area each having a tlat face adapted to abut against one another during make periods of the apparatus.

lt is another important object of this invention to provide breaker point apparatus including a wear-resistant stabilizing block assembly for continuous engagement with at least one point of the hexagonal cam conventionally forming a part of distributor mechanisms, such stabilizing assembly beinC disposed oppositely to the contact actuator of the breaker point apparatus for minimizing the effects of jitter due to wear of the journaling for the cam, thereby providing greater accuracy of dwell time.

lt is another important object of this invention to provide breaker point apparatus wherein the movable, platelike Contact is adapted for rotative movement relative to the stationary, plate-like contact, in order that such wear as may occur upon the abutting faces of the two contacts will be uniformly distributed to maintain a maximum of interengaging contact arca when the apparatus is in its make condition.

Still another important object of this invention is to provide breaker point apparatus adapted for mounting within a conventional distributor mechanism in unique manner requiring no modification of the standard` distributor mechanism and achieving improved accuracy of dwell time and contact operation through precise placement of the cam operated, contact actuator relative to the cam.

Yet other objects and advantages of the improved breaker point apparatus of this invention, including its unique economy from a manufacturing cost standpoint,

Patented Oct. 3G, 1%56 its improved positiveness of operation and various important details of construction, will be made clear or become apparent as the following specification progresses.

ln the accompanying drawing:

Figure l is a top plan View of a conventional mechanism showing the on distributor apparatus of this invention in e"ative position therewithin;

' 2 is a cross-sectional view taken on line II-II of Fig l; and

Fig. 3 is a top plan View or a modified form of the apparatus in place in a conventional distributor mechanism.

in the drawing, the numeral .ll-ll generally designates a conventional distributor mechanism, such as utilized in the internal combustion engines of automobiles, trucks, boats and the like, having a base l2 through which extends a rotatable shaft 1dcarrying a polygonal cam 16 provided with a cam surface having a number of raised peripheral points 1S. A breaker point pivot pin 20 also extends from base 12 of distributor mechanism lli in spa-ced parallelism to shaft -i and the axis of rotation of cam 16, pin 20 being normally utilized, when conventional breaker point assemblies are employed, for mounting a breaker point holding bracket.

The apparatus of this invention is composed of a breaker point assembly generally designated 36 and a stabilizing block assembly generally designated 4i), the latter being preferably, although not necessarily, provided.

Breaker point assembly includes a plate-like mounting bracket and breaker point device broadly desig- Device is mounted upon bracket 32 by any aste ing means such as screws 35, it being noted screws are llush with the face of bracket 32 oppo- '-.e 3 in order to nermit flat mounting of bracket upon base i2 of dist tor mechanism 1t), as most clearly illustrated in Bracket 32 is provided with slots and f ring moutning screws 44 and 46 respectively, f utilized for securing bracket 32 upon base l2 by means cf the threaded holes conventionally provided in the base l2 of a standard distributor mechanism 1b.

Since the manner of mounting the pivot pin 20 upon base l2 of the distributor mechanism 1i? forms no part of this invention, saine is not detailed in the drawing; however, the manner in which same extends from base 12 will be clear particularly from Fig, 2, it being understood that, if bracket 32 extends under that portion of device 34 which receives pin 2li, bracket 32 will be provided with a perforation to clear pin 26. With the advantageous construction contemplated by this invention, however, it will be clear that bracket 32 need not extend under such portion of device Device 34 includes a unitary, nylon plastic material having a cam follower extension portion 54. Main portion 52 of body Si) is provided with a straight elongated opening 56 therethrough adapted to tightly, but pivotally, receive pin 2l) of distributor mechanism lil. lt will now be clear that by the mounting of main portion 52 of body 50 directly upon pin Ztl extreme accuracy of placement is achieved with final adjustment of the positioning of device 3d relative to cam 16 being effected by swinging of device 34 and bracket 32 about pin 2t) before screws 44 and 46 are tightened upon bracket 32.

Main portion 52 of body 5@ is also provided with a straight elongated bore (nl having its longitudinal axis substantially perpendicular to, but spaced from, the longitudinal axis of pin receiving opening 56. When device 34 is in its operative position within mechanism 10, the longtudinal axis of bore di) will be disposed substantially radially ofthe axis of rotation of cam 16.

Bore 6l? is preferably shouldered as at 62 adjacent the end thereof opposite extension portion 54, there being block-like body 50 of main portion 52 and a an opening 6d defined by shoulder 62 of sufficient diameter to clear an elongated rod 6o which is reciprocably received within bore 6b and normally extends from the latter at both ends thereof. iiod oo has a portion 63 thereof of increased diameter adapted to slidably engage the Walls of main body portion 52 defining bore 61B, it being noted that both bore 61B and rod portion 63 are preferably cylindrical in or-der to permit rotation of portion 68 relative to body 50. Rod 66 is preferably, although not necessarily, formed of metal, the wear-resistant qualities of the nylon used for body being sucient to satisfy this requirement.

Rod portion 68 is yieldably biased into contacting relationship with a face 71B of that part of extension portion 54 of body 519 which is in spaced alignment with the end of bore 611 opposite shoulder 62 thereof by a coil spring 72 oppositely bearing upon enlarged rod portion 68 and shoulder 62 of main body portion 52. Cam follower extension 54 is provided with a cam engaging point 74, and a section 76 of reduced thickness at the zone of interconnection between extension portion 54 and main portion 52 of body Sti. Section 76 is of sufficient flexibility, due to its decreased thickess and the properties of the nylon plastic of which body Si? is formed, to permit swinging of extension portion 5d relative to main portion 52 of body 511 whenever point 74 of cam follower extension 54 is engaged by a point 1S of cam 16. Such swinging of cam follower extension 54 toward main body portion 52 reciprocates rod 65 in the direction of shoulder 62 by virtue of the interengagement between face 70 and rod portion 63, the spring 72 obviously being cornpressed during such operation for return of rod 66 and follower extension 54 in the opposite direction when point 74 of follower extension 54 is engaging a portion of the surface of cam 16 between points 1S of the latter.

A metallic contact plate 7S, preferably of silver or other highly conductive material, is securely mounted upon main body portion 52 by screws or the like 80 and is provided with an opening 32 of sufficient diameter to clear that portion of rod 6o extending therethrough without electrical contact therebetween. Means for making an electrical contact with plate 78 preferably comprise a lug or the like 34 secured under one of the screws 8i) and having a conductor wire $6 connected therewith.

Mounted upon the end of rod do opposite enlarged portion 68 thereof is an annular contact disk fig having a flat face 90 adapted to uniformly engage the outward, at surface 92 of plate 7 3 when the rod 66 is reciprocated under the influence of spring 72 in the direction of extension portion 54, as occurs when point 74 is between points 18 of cam 16. Although contact disk 8S could be mounted upon rod ,65 in various fashions, the preferred manner of mounting same is by the provision of a portion 94 of reduced diameter on rod 66, which portion passes through the perforation 96 of annular disk 88 and is then crimped as at 93 upon disk S8 oppositely to face 90 of the latter. Electrical connection with disk 88 may preferably be made by the provision of a lug or the'like 113@ in contact'with disk and between the latter and the crimped portion 98 of rod 66, lug 14N) being provided with a conductor wire 16?. connected therewith.V It may be noted that screws Sti are preferably disposed adjacent the corners of rectangular plate 78, in order to be clear of the area of engagement between annular disk 8S and surface 92 of plate 78.

It will now be clear that the structure contemplated by this invention provides a maximum of electrical contact area between face 9u of disk 58 andV surface 92 of plate 7S for the dimensions of device 34 permitted by the construction of the distributor mechanism 11i in which it is to be used. Moreover, since it .is clear that continued reciprocation of rod 68 against and under the influence of spring 72 will effect a gradual rotation of rod 66 within bore 60, and therefore of disk 8S relative to plate 78,it will be apparent that any wear upon face 7 and surface 78 will be uniform so that eective engagement between substantially the entire zones thereof is accomplished each time the rod 66 is reciprocated by spring 72 toward cam follower extension S4. It is this last mentioned fact that largely accounts for the increased current flow, and accordingly improved performance, characteristic of the breaker point apparatus of this invention. Moreover, it will be apparent that the manufacture of device 34 and its associated bracket 32 involve simple manufacturing procedures and a minimum expenditure of materials resulting in greatly decreased costs.

Referring now to the stabilizing block assembly 40, it will be seen that same consists of a block 104 of nylon plastic material having a concave face 1% whose radius of curvature is equal to the radius of cam 16 measured at any of its points 18. Block liid is mounted by a screw or the like 1118 upon a metal holding bracket provided with one or more elongated slots 112 for receiving screws 114 which are attached to base 12 of distributor mechanism 1t). By adjusting the position of bracket 110 with screws 114i loosened in slots 112, and then tightening screws 114 to securely fasten the bracket 110 upon base 1?., resistant block 104 may be positioned for just engaging the points 18 as they rotate thereby. Stabilizing block assembly 4t), accordingly, is adapted for maintaining the axis of rotation of cam 16 `against vibration or jitter toward and away from the point 74 of cam follower extension portion 54 of the device 34. Since the journaling of shafts 14 are often subject to wear, particularly in the distributor mechanisms 1t) of o-lder internal combustio-n engines, it will be appreciated that the provision of stabilizing assembly di), by removing such undesirable jitter or play from the cam 16, permits precise positioning of device 34 and bracket 32 for the exact amount of dwell time between contact face 9th and contact surface 92 which is required for optimum op eration of the engine with which the distributor mechanism 1t) is associated. As is well known to those skilled in the art, maximizing the period of dwell or make between contact surfacesis to be desired by virtue of the increased period of ignition time achieved thereby. Obviously, in a distributor mechanism 10 having worn journaling for cam shaft 14. this result is best attained when the stabilizing block 40 is included as a part of the breaker point apparatus.

Referring now to Fig. 3, there is illustrated a modi ed form of the apparatus of the invention, which at least from the standpoints of manufacturing economy and ease of assembly is the currently preferred form of the invention. Such modified apparatus utilizes, instead of the separate device 34 of nylon plastic or the like, and the metallic bracket 32 attached thereto, a single unitary body generally designated 26@ preferably of nylon plastic material and having a main block portion 202, a cam follower extension portion and a mounting extension portion 2%. Like numbers in Fig. 3 designate similar or identical parts to those so numbered and described in connection with Figs. l and 2.

The principal differences between the modified form of the invention shown in Fig. 3 and the form shown in Figs. 1 and 2 will be seen to include the provision of the mounting portion 266 as an integral part ofthe device Zitti, the provision of an elongated opening 208 in mounting portion 2% with an eccentric adjusting screw 210 secured in base 12 and adapted to movethe device 211i) toward or away from cam 16 when the screw 211) is rotated, the provision of a washer 212 between spring 72 and stationary contact plate 78 (instead of the shoulder 62 shown in Fig. 2), and the different configuration of that section 214 of main block 2t2 which is provided with the perforation S6 for pivotally receiving pivot pin 2i) and to which the cam follower extension portion 2% is interconnected through a section of reduced thickness concave face 1% of the nylon, wearV This construction illustrated in Fig. 3 tends to minimize the use of materials and to provide a sturdy device 200 formed in its entirety, except for the rod 66 and the contacts 78 and 88, of extremely wear-resistant maten'al. It will be understood that the mounting extension portion 206 of device 200 is of substantially lesser thickness than the main block portion 202. The -device 200 may thus be easily and economically formed by molding of the plastic material mentioned by techniques conventionally and well known to that art.

In principle, the operation of the device 200 is substantially the same as that described for the device 34. The use of a separate mounting bracket 32 or of an integral mounting extension 206 will thus be perceived to be somewhat optional, although as stated, the construction of Fig. 3 is presently preferred.

It will now be apparent that the structure above described is manifestly adapted for achieving the objectives of this invention which were recited above. It will also be obvious, that certain minor modifications and changes could be made from the exact structure disclosed without departing from the true spirit and intention of the invention. Accordingly, it is to be understood that this invention shall be deemed limited only by the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A breaker point assembly for an internal combustion engine having a distributor mechanism including a base and a rotatable cam, said assembly comprising, in combination, a body of insulating material having an elongated bore therethrough; means adapted for mounting the body on said base with the longitudinal axis of the bore disposed substantially radially to the axis of rotation of the cam; an elongated rod reciprocably mounted in the bore and normally extending beyond both ends of the latter; means swingably mounted on the body and adapted for extending between and oppositely engaging the cam and one end of the rod for translating the rotary motion of the former into reciprocatory motion of the latter; means for yieldably biasing the rod in one direction toward the cam; a plate of conductive material having an opening therein of suicient dimension to clear said rod; means mounting the plate on the body on that surface of the latter remote from the cam, the opposite end of the rod extending through said opening and beyond said plate; means for making an electrical connection with the plate; a movable contact element; means mounting the element on the rod adjacent said opposite end of the latter and for reciprocation therewith, said element being disposed to engage the plate when the rod is reciprocated in said one direction and to move out of engagement therewith when the rod is reciprocated in the opposite direction; and means for making an electrical connection with the element.

2. In an assembly as set forth in claim 1, wherein said element comprises an annular, disc-like plate disposed to engage the first-mentioned plate throughout a continuous zone of the latter circumscribing said opening when the rod is reciprocated in said one direction.

3. In an assembly as set forth in claim l, wherein said means for translating motion of the cam into motion of the rod comprises a swingable cam follower extension on the body and integral therewith, said extension including a relatively flexibie section of reduced cross section adjacent the zone o juncture of the extension with the remainder of the body.

4:. In an assembly as set forth in claim l, wherein is provided a wear resistant member having an arcuately concave face; and means adapted for adjustably, but rigidly and stationarily, mounting the member on the base for engagement of said face of the member on that surface of the cam remote from the body.

5. A breaker point assembly for an internal combustion engine having a distributor mechanism including a base, a pivot pin extending from the base, a rotatable shaft extending from the base in spaced parallelism to the pin, and a cam carried on the shaft, said assembly comprising, in combination, a unitary body of wear resistant plastic material having a main, block-like portion provided with a straight, elongated hole adapted to pivotally receive said pin and a straight, elongated bore therethrough having its longitudinal axis adapted for disposition substantially radially of said shaft when the body is pivoted to an operative position upon said pin, and an elongated cam follower portion extending from said main portion and provided with a part disposed in alignment with the bore and in spaced relation to said main portion and a section of reduced thickness and sutiicient flexibility to permit swinging movement of said part toward and away from said main portion; means adapted for holding the body in said operative position on the base, said cam follower portion being adapted to engage the cam when the body is in said position for swinging of said part relative to said main portion when the shaft is rotated; a straight, elongated rod reciprocably mounted in the bore and normally extending beyond both ends of the latter; means for yieldably biasing the rod in one direction to maintain one end of same in engagement with said part of the cam follower portion; a metallic contact plate having an Opening therein for clearing the rod, said plate having a flat face; means mounting the plate on said main portion with the rod extending through the opening and said face facing away from the main portion and the cam and disposed in a plane perpendicular to the longitudinal axis of the rod; means for making an electrical connection with the plate; a contact disc having a iiat annular surface; means mounting the disc on the other end of the rod for reciprocation therewith, said surface of the disc facing and being substantially parallel to said face of the plate, whereby, as the shaft is rotated the cam follower is swung toward and away from said body portion to reciprocate the rod for moving said surface of the disc alternately into and out of engagement with said face of the plate; and means for making an electrical connection with the disc.

References Cited in the file of this patent UNITED STATES PATENTS 1,313,856 Cavanagh Aug. 19, 1919 2,106,721 Chermendy Feb. 1, 1938 2,520,237 Cleary Aug. 29, 1950 2,664,474 Chermendy Dec'. 29, 1953 FOREIGN PATENTS 189,722 Switzerland May 18, 1937

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