Electrical connector assembly with locking arms and locking planes

An electrical receptacle connector for mating, along a vertical direction, with a plug connector having corresponding blade type contacts therein, comprising:

• an insulative receptacle housing with a plurality of female contacts and locking pieces retained therein, said female contacts being paired and each pair of female contacts including a pair of resilient contacting arms, and each locking piece including a pair of locking arms;
• wherein
• the receptacle housing includes a plurality of passageways each being equipped with one pair of female contacts and one locking piece;
• wherein in each passageway, the pair of corresponding contacting arms are opposite to each other in a first direction perpendicular to the vertical direction, and the pair of corresponding locking arms are opposite to each other in a second direction perpendicular to both the vertical direction and the first horizontal direction.

An electrical plug connector for mating, along a vertical direction, with a receptacle connector having a plurality of passageways with a plurality of paired female contacts and locking pieces therein, respectively, comprising:

• an insulative plug housing;
• a plurality of blade type male contacts retained in the plug housing and adapted to be inserted into the corresponding passageways respectively, each of said male contacts forms a pair of primary mating planes opposite to each other in a first horizontal direction perpendicular to the vertical direction, and a pair of side locking planes opposite to each other in a second horizontal direction perpendicular to both the vertical direction and the first horizontal direction;
• wherein
• a pair of locking notches are formed in the corresponding locking planes, respectively.