Cam lock spark plug wire connection

Electrical connectors – Having spark or glow plug cover – With distinct securing means

Reexamination Certificate

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Details

C439S818000, C123S1690PH

Reexamination Certificate

active

06193528

ABSTRACT:

TECHNICAL FIELD
The field of this invention relates to a spark plug and wire connection for an internal combustion engine.
BACKGROUND OF THE DISCLOSURE
A solid electrical connection of the high voltage wiring to the spark plug installed is of utmost importance in an internal combustion engine that uses an electrical spark for cylinder ignition. An electrical connection needs to be maintained from the wiring to the spark plug terminal in an extreme ambient environment. Any device that is used to maintain the connection needs to withstand vibration, high engine temperatures, and grease, dirt and water sprayed onto the connection. The connection also should suppress radio frequency interference. Furthermore, any designed connection also needs to interface with any readily available SAE standard spark plug design, and needs to interface with other engine parts without modification to the engine parts. The spark plug connection also needs to be expeditiously and economically manufactured.
While known spark plug connection designs have met these above listed design requirements, none of them have provided connection position assurance and provide a secondary lock to reduce the possibility of inadvertent disconnection from the spark plug.
What is needed is an expeditiously manufactured spark plug wire connection that provides for a secondary lock and a connection position assurance.
SUMMARY OF THE DISCLOSURE
In accordance with one aspect of the invention, a spark plug wiring terminal is selectively connected to a post of a spark plug. The post has an annular groove in proximity to its distal end. The wire terminal has an end constructed to receive the spark plug post and has at least one lateral notch in proximity to its distal end. A snap ring is constructed to extend laterally through the notch of the terminal to engage the spark plug post annular groove and is expandable along an operating axis to allow disengagement from the spark plug post. The snap ring is preferably made from spring steel and is normally biased to the engaged position with the annular groove in the spark plug post.
A lock body is mounted about the terminal for relative rotation with respect to the terminal and snap ring. The lock body has an opening that surrounds the snap ring and has a major and minor axis. The major and minor axis are respectively dimensioned such that when the major axis is aligned with the operating axis of the snap ring, the opening allows the snap ring to expand and be disengaged from the spark plug post. When the minor axis is aligned with the operating axis of the snap ring, the lock body blocks the snap ring from expanding which prevents disengagement from the annular groove in the spark plug post. Preferably, the opening is shaped in the form of an oval.
An outer shell desirably surrounds the lock body circumferentially and is rotationally affixed to the lock body. The outer shell preferably functions as a heat shield. A lower section of the outer shell is shaped to slidably receive and be rotationally affixed to the spark plug. It is preferred that the lower section of the outer shell has a hexagonal shaped lower opening that fits a hexagonal section of the spark plug. An upper section of the outer shell has a first portion of locking mechanism. In one embodiment, a bushing is interposed between the lock body and the outer shell.
A cap is connected to the terminal and rotatably affixed to the terminal such that both the terminal and cap are rotatable with respect to both the lock body and the outer shell. The cap has a second complementary portion of the locking mechanism to normally retain the cap member and the terminal in the locked position with respect to the first portion of the locking mechanism on the outer shell. It is desirable that the first portion of a locking mechanism includes a rising cam that extends from an unlocked position toward the locked position with a recess at the end of the cam to receive a portion of the cap when the cap is in the locked position. The recess at the end of the cam has an abutment shoulder adjacent thereto that normally prevents the cap from rotating to the unlocked position out of the recess.
The cap has a handle section for manual operation and a depending flange for riding on the cam of the outer shell. The recess receives the flange to retain the cap in the locked position.
In one embodiment, the cap is made from a resilient deformable plastic material to allow the depending flange to deform and ride out of the recess and over the abutment shoulder when a rotational force over a predetermined amount is applied on the cap.


REFERENCES:
patent: 5011439 (1991-04-01), Pawlicki
patent: 5630722 (1997-05-01), Mchizuki et al.

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