Electrical Connector for a Distributorless Ignition System

1. Field of the Invention

The invention is related to electrical connectors and, in particular, to an electrical connector for a distributorless ignition system.

2. Description of the Prior Art

Electrical connectors for the ignition systems of internal combustion engines are designed with two objectives in mind. The first is to make good reliable electrical connections at both the spark plug and at the source of the high voltage ignition signal, and the second is to isolate these electrical connections from the dirt and hostile environment encountered under the hood of an automotive vehicle. To protect the electrical connection, the prior art teaches the use of rubber or rubber-like boots as taught by Candelise in U.S. Pat. Nos. 3,076,113; Goldowsky in 3,911,203; and Fitzner in 3,965,879. Fitzner also teaches a metal electrostatic shield which completely encloses the insulator boot. This metal electrostatic shield is electrically and mechanically attached to the spark plug by a lip which engages the underside of the spark plug's hex nut and which is held in place by a coil spring. Rabezzana in U.S. Pat. No. 2,296,054 teaches a Bakelite cover for the electrical connection between the spark plug wire and the spark plug which has a pair of spring loaded latches which engage the underside of the spark plug's hex nut to hold the Bakelite cover over the end of the spark plug.

Jones et al in U.S. Pat. No. 3,876,280 teaches a bi-metal connector for underground electrical distribution systems which has a neoprene boot molded or bonded inside a rigid plastic housing. The neoprene boot covers the electrical connection between the cable and the terminal and makes a watertight seal with the external surface of a conical receptacle of a transformer or other high voltage device. Roman, Jr. in U.S. Pat. No. 4,225,206 teaches a multiple lead connector for a fuel injector or similar type device having a central boss flanked by a pair of pin terminals. The connector has a structural plastic housing from which pivotably depends a pair of diametrically disposed latch members. The latch members engage the underside of an enlarged head of the fuel injector's central boss to lock the connector to the fuel injector housing. An elastomeric boot or seal member is compressed between the fuel injector housing and the connector housing to form a watertight seal. In a somewhat similar manner, Margrave et al in U.S. Pat. No. 4,376,563 teach a multiple lead connector having a latch member securing the male and female halves of the connector. A peripheral elastomeric seal is compressed in an annular slot formed between the male and female portions of the connector to form a watertight seal. Finally, Stone in U.S. Pat. No. 4,268,101 teaches an electrical connector having a pair of integrally formed contact members which are biased towards each other so as to reliably contact a projecting male electrode. The contact members have arms extending external to the connector which when compressed towards each other release the integrally formed contact members from the male electrode.

The invention is an electrical connector for a distributorless ignition system which is addressed to the same problems encountered under the hood of an automotive vehicle as the electrical connectors for connecting the spark plug cable to the spark plugs.

The invention is an electrical connector for connecting the electrical terminal of a spark plug cable to a high voltage output terminal of a distributorless ignition system. The connector includes a tower member having an electrode for making an electrical connection between the electrical terminal of the spark plug cable and the high voltage output terminal of the distributorless ignition system and an insulator boot having a central bore for receiving a portion of the spark plug cable and a portion of the electrical terminal. The forward end of the insulator boot engages the tower member to make a watertight seal. The connector also has a retainer for locking the insulator boot to the tower member to maintain the watertight seal and to secure the electrical connection between the spark plug cable's electrical terminals and the tower member's electrode.

One object of the invention is to provide an electrical connector for securely connecting the electrical terminal of a spark plug cable to the high voltage output of a distributorless ignition system.

Another object of the invention is to provide a connector having means for releasibly locking the retainer to the tower member.

Another object of the invention is to accomplish locking of the insulator boot to the retainer to assure they will be withdrawn from the tower member as a unit.

A final object of the invention is to provide an electrical connector which provides a watertight seal about the connection between the electrical terminal and spark plug and the connection between the electrical terminal and the electrode of the tower member.

These and other objects of the invention will become more apparent from a reading of the detailed description of the invention in connection with the appended drawings.

FIG. 1 is a side view of the connector;

FIG. 2 is an end view of the connector; and

FIG. 3 is a cross-sectional side view of the connector showing the internal details thereof.

An electrical connector 10 for a distributorless ignition system is shown in FIGS. 1 through 3. The electrical connector 10 is used to secure the connection of an ignition cable to the individual coils of a distributorless ignition system, such as disclosed by Asik in U.S. Pat. Nos. 4,478,201 or Iwasaki in 4,382,430. In these distributorless ignition systems, each spark plug has its own (separate) capacitor or ignition coil for producing a high voltage ignition signal which is transmitted to the associated spark plug.

Referring to FIGS. 1 through 3, the electrical connector 10 has a dielectric tower member 12 which mounts directly in a well 56 of a housing 58 which encloses the distributorless ignition system. The tower member 12 is made from Bakelite or a structural plastic material having excellent dielectric characteristics which is highly resistant to electrical breakdown under high voltage conductions. The distributorless ignition system may embody one or more high voltage generators (ignition coils) as is known in the art. A threaded shaft 14 protruding from the base of the tower member 12 is threaded into a threaded bore on a high voltage terminal 60 fixedly attached to the housing 58. The threaded shaft 14 is an integral extension of a cup-shaped electrode 16, as shown in FIG. 3. An "O" ring 62 forms a watertight seal between the side walls of the well 56 and the tower member 12. Alternatively, the space between the tower member 12 and the walls of the well 56 may be filled with a potting material to form the watertight seal.

The cup-shaped electrode 16 i adapted to receive the free end of an L-shaped electrical terminal 18. The other end of the L-shaped electrical terminal 18 is mechanically connected to an ignition cable 20 and electrically connected to the conductive core 22. The electrical connection between the conductive core 22 and the L-shaped electrical terminal 18 may be made by the conventional strip and fold method as taught by Barker et al in U.S. Pat. No. 3,284,751 or any other method known in the art.

A portion of the L-shaped electrical terminal 18 and a portion of the ignition cable 20, including the mechanical and electrical connection therebetween, are protected from the environment by an insulator boot 24 made from an elastomer or rubber-like material. The insulator boot 24 has an annular recess 26 in which is received a cylindrical extension 28 of the tower member 12 to form a watertight seal therebetween.

A portion of the insulator boot 24 is enclosed in a retainer 30 made from a structural plastic, which locks the insulator boot 24 and the L-shaped electrical terminal to the tower member 12. As shown in FIGS. 1 and 2, the retainer has a pair of pivotably mounted latch members 32 and 34. Each of the latch members 32 and 34 have a dog catch 36 which engages the underside of a radial flange 38 provided about the periphery of the tower member 12 to lock the retainer 30 to the tower member. The latch members 32 and 34 are formed integral with the retainer 30 and are resiliently biased by pivot bars 40 and 42 so that the dog catches 36 are biased towards each other and into engagement with the radial flange 38. The latch members 32 and 34 each have an arm 44 which extends upward from the pivot bars 40 and 42 in a direction opposite the dog catches 36. Gripper pads 46 provided at the ends of each of the arms 44 permit a service person to compress the arms 44 towards each other as indicated by arrows 48 and 50, pivoting the dog catches 36 away from each other and disengaging them from the radial flange 38. With the dog catches disengaged from the tower member's flange 38, the retainer 30 can be freely withdrawn from the tower member 12, disengaging the L-shaped electrical terminal 18 from the tower member's cup-shaped electrode 16.

To ensure that the insulator boot 24 will be withdrawn from the tower member 12 with the withdrawal of the retainer 30, a lock tab 52 is provided on the internal surface of the retainer 30 which engages a notch or recess 54 provided in the insulator boot 24. The engagement of the lock tab 52 in the notch 54 locks the insulator boot 24 in the retainer so that these two elements do not separate from each other during the disconnection of the retainer 30 and the L-shaped electrical terminal 18 from the tower member 12. Alternatively, the retainer 30 may be insert molded into the insulator boot 24 making a unified assembly eliminating both the lock tab 52 and the notch or recess 54.

It is recognized that the configuration of the various components of the electrical connector may be changed from those shown in the drawings without departing from the spirit of the invention as described herein and set forth in the appended claims. For example, a twist lock may be used in place of the latches to lock the retainer to the tower member or the lock tab which locks the insulator boot to the retainer may be provided on the insulator boot rather than the retainer and the notch for receiving the lock tab provided in the retainer. These types of modifications are fully within the scope of the invention as described herein.