Connector with selectivity key

April 9, 1963

3,085,221

J. F. KELLY

CONNECTOR WITH SELECTIVITY KEY

Filed Sept. 27, 1960

<img file="US3085221A_D0001.tif" />

3,085,221

Patented Apr. 9, 1963

United States Patent Office

3,085,221

CONNECTOR WITH SELECTIVITY KEY Joseph Francis Kelly, Scottsdale, Ariz., assignor to Cannon Electric Company, Los Angeles, Calif., a corporation of California

Filed Sept. 27, 1960, Ser. No. 58,717

Claims. (Cl. 339—186)

This invention relates to electrical connectors and in particular to a plug and receptacle combination in which a plurality of mating contacts are mounted, and features means for orienting (or polarizing) the plug and receptacle prior to coupling them so that correct alignment and junction of the respective contacts is assured.

While the problem mentioned is encountered in a single connector which, for example, utilizes a uniform pattern for arrangement of the terminals and if not somehow oriented could be brought together in reverse, that is to say, 180 degrees out-of-phase, the invention has an even greater importance in a rack and panel installation where several identical electrical connectors are mounted in close proximity and it is desirable that polarization means be provided whereby a given plug can be mated with one, and only one, receptacle.

Prior to the present invention correct mating has been accomplished by varying the contact lay-out pattern or by providing two adjustable aligning keys of sufficient length to prevent connector engagement prior to polarization. The first method is unduly expensive and the second is space consuming.

It is an object of the present invention to provide a means of keying an electrical connector plug to a receptacle so that correct selective engagement is assured. More specifically the invention contemplates the accomplishment of the stated objective by a selectivity key and key way which are contained within the general physical boundaries of the necessary structure for the plug and receptacle.

A further object is to provide in a device of the character described a selectivity key and means for mounting it in one of the mating connector parts and a keyway structure and means for mounting it in the opposite of the mating connector parts, the mounting means in both cases being adjustable to different radial positions whereby with a single form of key and keyway, many different polarizing combinations can be obtained by adjustment or resetting of the key and keyway structure.

These and other objects of the invention will be made more fully apparent from a consideration of the description which follows, taken in conjunction with the drawing.

In the drawing:

FIGURE 1 is a perspective view of a connector plug embodying the key portion of the present invention;

FIGURE 2 is a perspective view of the receptacle to be coupled with the plug of FIGURE 1 and embodying the keyway structure;

FIGURE 3 is a perspective view with parts cut away of the plug and receptacle joined together;

FIGURE 4 is an exploded perspective view of the principal parts making up the key and keyway structures; and

FIGURE 5 is an assembled perspective view of the parts shown in FIGURE 4.

There is illustrated a plug 10 and a receptacle 11, the plug being provided with a plurality of electrical contact sockets 12 all alike and arranged in a geometrical pattern. The receptacle 11 contains pin contact members 13 of the correct size and pattern arrangement to engage with the sockets 12 for completing electrical connections in a plurality of circuits represented by conductors 14 and 15. The detailed type of contact members and the means of soldering, crimping or otherwise attaching the conductors to the contact members may be conventional or otherwise, as desired.

Noting that the arrangement, shape and size of the contact members 12 and 13 is such that unless otherwise prevented, the plug could be inserted into the receptacle either in the relative position shown in FIGURES 1 and 2, or with one of the parts inverted 180 degrees, which latter would cause circuit failures, the object to be accomplished is to insure proper polarization, namely correct orientation of the plug and receptacle. The means for doing this is mounted on flanges 20 and 21 of the plug and receptacle, respectively. The flange 20 is part of a back or base plate 19, extending marginally outside the boundaries of a shell 22 which houses an insulating block 23, which in turn, contains the sockets 12.

The flange 21 may be the marginal portion of a boxlike structure or receptacle 24 which houses an insulating plate or member 25 which in turn mounts the pin contact terminals 13. The flange 21 is formed with an opening 26, coincident in area with walls 27 of the receptacle 24, such walls, together with the face of the insulator block 25 affording a receptacle for entrance of the shell 22 of the plug. When the plug and receptacle are joined, the flanges 20 and 21 are generally coincident in outline; their confronting surfaces are substantially parallel and in relatively close proximity.

With the foregoing background we now turn to a description of the polarizing means. In the outward face 30 of the flange 20 is formed a circular countersink 32. Joining the countersink 32 and completing an opening through the flange is a hexagonal passage 33, the greatest diameters of which are coincident with the diameter of the countersink 32.

A key 35 comprising an elongated stem 36 and a hexagonal head 37 flanked by a circular flange 38 is mounted upon the plate flange 20 in the following manner: The hexagonal head 37 is fitted into the hexagonal bore 33, the respective dimensions being calculated for such purpose, and axial movement in a direction from right to left as seen in FIGURE 4 is stopped by abutment of the chord portions of the circular flange 38 coming in contact with the inner face 40 of the plate 21. The key stem is shown as generally hemicircular in cross section. The head 37 and flange 38 correspond roughly to what is known as the bow of a conventional door lock key.

A circular washer 41 is seated in the circular countersink 32, and a screw 42 extending through the washer makes threaded engagement in a tapped hole 43 in the key head 37. It should be noted that with the use of a hexagonal head 37 as described six different circumferential positionings of the key blade 36 are available. Other equilateral polygonal shapes may be employed.

A key assembly generally designated by the numeral 45 and identical to that already described is located at the opposite end of the plate 19.

The keyway assembly heretofore referred to is generally designated by the numeral 50. Provision for its mounting in the flange 21 of the receptacle is afforded by a circular countersink 51 in the back face 52 of the flange, and a bore completed through the flange by junction of the countersink with a hexagonal bore 53, the countersink and the hexagonal bore being similar to the countersink and bore in plate 19.

A keyway plug structure 54 is formed with a hexagonal head 55 adapted for firm mounting in the hexagonal bore 53 and is associated with a circular disc 56 which seats in the countersink 51 when the parts are assembled.

The hexagonal section 55 is formed with a groove 60 intended for the reception of a C-ring 61. The hexagonal section is also formed with a notch 62 immediately adjacent the inside surface of the disc 56. This notch is made deep enough to communicate with an axial bore 63

3,085,221 which extends through the entire member 54. The notch is for the reception of a key stop 64 which when in place blocks off a chord of the bore 63, providing a keyway afforded by the remainder of the bore and adapted to slidably receive the stem 36 of the key 35.

As noted, the stem of the key is flat on one side and oval on the other to match the chord of the keyway.

A duplicate keyway structure generally indicated as 70 is positioned at the end of the flange 21 opposite the keyway structure 50.

The keyway structure is assembled with the receptacle flange 21 by installing the hexagonal section 55 in the hexagonal bore 53 with the circular disc 56 nesting in the countersink 51 and that portion of the hexagonal section to the left of the groove 60 as seen in FIGURE 4 extending axially beyond the surface 64 of the flange a sufficient distance to expose the groove 60, and the C-ring 61 is snapped into the groove to lock the assembly together as shown in FIGURE 5.

The length of the key stem in relation to the length of the contact pins 13 is such that the key stem must pass the stop 64 in the keyway plug before any contact occurs between the pins 13 and sockets 12.

It should be apparent that if the stem of one key is suitably aligned with the unrestricted portion of a bore 63 which affords the keyway, and the same condition obtains at the other end of the plug and receptacle, the two parts may be joined for completing the connection. If there be any misalignment of key and keyway the connection cannot be made.

While the key stop 64 has been shown as a relatively simple type conforming exteriorally to the hexagon section 55, and having a straight edge 65 forming the chord line of the keyway, it should be apparent that the key stop 64 could be formed with variations in substitution of the straight edge 65, and the stem of the key 35 could be designed to cooperate therewith.

While the instant invention has been shown and described herein what is conceived to be that most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.