Patent ID: 7170749

Claim:
An electrical apparatus comprising: a case which is configured to have an opening in a front wall; a motherboard which is positioned far behind the opening made in the case, with one surface faced to the opening; a daughter board which has been inserted into the case through the opening; a slot which is provided between the opening and motherboard, and guides the side edge of the daughter board extending in a inserting direction of the daughter board; an extension board which is placed between the motherboard and at least one daughter board; a first receptor which is mounted on the motherboard facing and opposed to the opening; a first connector which is provided at an insertion side of the extension board, is inserted in the first receptor and extends perpendicular to the one surface of the motherboard; a second receptor which is provided at an opening side of the extension board, with each terminal conducted to one terminal of the first connector; a second connector which is provided at an insertion side of the daughter board and is inserted in the second receptor; and a holder which is fixed to the extension board, has a flexible lock piece to cover the second connector connected to the second receptor, and has a hook to stop extracting the second connector from the second receptor at a distal end of the lock piece, wherein the holder has an interference projection at the distal end of the lock piece, said interference projection protrudes in a direction leaving the second receptor and sticks in the inlet of the second connector immediately before inserted into the second receptor when the daughter board approaches the extension board along the slot.