Automotive ignition contact points

Nov. 1, 1955 R SKAY 2,722,584

AUTOMOTIVE IGNITION CONTACT POINTS

Filed July 12, 1952

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ΗΤΤσΗΝΕΎ

2,722,584

Patented Nov. 1, 1955

United States Patent Office

2,722,584

AUTOMOTIVE IGNITION CONTACT POINTS 5

Frank Skay, Detroit, Mich., assignor to Holley Carburetor Company, Detroit, Mich., a corporation of Michigan

Application July 12,1952, Serial No. 298,496 io

Claims. (Ci. 200—166)

R and O are two slots in N to permit the bracket N to be adjusted around its insulated pivot Q which locates on the plate S.

The Figures 3 and 4 show a stationary positive contact H with cavity L mounted on bracket C of entire bracket N.

J is the negative contact mounted on the breaker arm E.

Figure 5 shows the direction of transfer of the metal when the contact H (stationary) is positive.

Figure 6 shows the direction of transfer of the metal when the moving contact A is positive.

The object of this invention is to prolong the life of the contact points of a pair of ordinary tungsten contact points on the low tension side of an automotive ignition system.

The characteristic failure of such points is caused by the transfer of metal from the plus to the minus side, which produces the well known pyramid effect and thus shortens the life of the pair of contact points. By distributing the “build up” around a pre-formed crater in the positive contact, I have gained an improved life.

Figure 1 shows the preferred form of my invention.

Figure 2 shows a cross-sectional elevation on plane 2—2 of Figure 1.

Figure 3 shows an alternative construction.

Figure 4 shows an enlarged cross section elevation corresponding to Figure 2.

Figure 5 shows the transfer of metal with construction shown in Figure 3.

Figure 6 shows the transfer of metal with construction shown in Figure 2.

In the figures:

A is the moving positive tungsten point having a cavity K mounted on an arm E.

B is the stationary negative tungsten point without any cavity mounted on an upright C of a bracket N.

D is the insulated rubbing block which engages with a cam (not shown) and causes the arm E to move and the contacts A and B to open and shut.

F is the spring which forces the rubbing block D into engagement with the cam (not shown). F is also a conductor leading current from electrical connection M. The stationary contact B and the arm C are all integral with the entire bracket N adjustably mounted on plate S.

Operation

1. The movement of the arm forces air into the cavity, cushioning the impact of the two contacts; and

2. At the same time provides cooling.

3. Tungsten metal transfer from the cavity side pre₂θ vents any confined central interference such as a high area within a cavity.

4. Pressure created in the center of the contacts when closed reduces arcing when they break.