This invention relates to electrical connectors, and in particular to keying structures therefor.
Electrical connectors may be provided with keying structures to permit predetermined pairs of connectors to mate with each other and to prevent the mating of connectors which are not intended to be mated with each other. Keying structures are usually provided on connectors when a plurality of identical connectors are positioned in situ in close proximity to one another so that there is the risk of the wrong connectors being mated therewith. Keying structures do not interfere with the mating of connectors that are intended to be mated with each other but provide interference with the mating of connectors that are not intended to be mated with each other, so as to prevent such mismating.
The keying of connectors is to be distinguished from the polarization of connectors, in that polarization ensures that a first connector which is matable with a second connector is properly oriented relative to the second connector for mating; whereas keying provides a mechanism which permits the mating of connectors which are intended to be mated with each other but prevents the mating of connectors which are not intended to be mated with each other even if they are properly oriented with respect to each other.
U.S. Pat. Nos. 4,822,305 and 4,832,624 disclose keying systems in which a key member is secured to one of the pair of complimentary connectors and is adapted to cooperate with an opposing key member secured in the other connector of the pair.
Each key member is secured in its connector in a selected orientation with respect to its opposing key member so that when the connectors are intended to be mated, extended portions on the key members pass by each other during mating to allow the connectors to mate. If one of the key members is secured in an orientation that is not complimentary to its opposing key member, the extended portions on the key members will engage one another during mating to prevent the connectors from mating. U.S. Pat. No. 4,929,184 disclose a keying system comprising parts which are securable to metal flanges on an electrical connector.
There is disclosed in U.S. Pat. No. 4,934,950 an electrical connector having keying means which are securable in one of a plurality of different angular orientations in a plastic housing.
U.S. Pat. No. 3,491,330 discloses an electrical connector having keying members to each of which a bushing can be locked in one of several possible angular orientations.
According to U.S. Pat. Nos. 3,582,867 and 4,895,535 keying means are securable in one of several possible angularly orientation in a flange of a connector.
U.S. Pat. No. 4,181,391 discloses connectors having keying devices mounted to corresponding flanges of the connectors in one of a plurality of angular orientations. The connectors are securable together by means of jackscrews surrounded by keying structures.
U.S. Pat. No. 4,457,575 discloses a connector having an insulating housing provided with a metal shield. Keying means are formed integrally with the housing forwardly of the shield.
United Kingdom Patent 961,714 discloses a connector having a multi-part keying assembly removably received in a recess in an insulating housing of the connector. The keying assembly includes a rotatable pin having a hexagonal flange at one end and an axial keying spline at the opposite end of the pin.