Patent ID: 8188711

Claim:
A charger adapted to charge either one of a first-type battery pack and a second-type battery pack, wherein both of the first-type battery pack and the second-type battery pack have an insertion portion respectively, the shape of the insertion portion of the first-type battery pack is different from the shape of the insertion portion of the second-type battery pack, and a concave portion is formed on the insertion portion of the second-type battery pack, the charger comprising: a housing having a battery pack socket into which the insertion portion of the first-type battery pack and the insertion portion of the second-type battery pack can be selectively inserted in respective prescribed attitudes, wherein the battery pack socket has a partial area for commonly accepting the insertion portion of the first-type battery pack and the insertion portion of the second-type battery pack, at least one non-retractable projecting portion is formed within the battery pack socket in an area of the battery pack socket where the second-type battery pack fits but the first-type battery pack does not fit, the at least one projecting portion is configured to enter into the concave portion formed on the insertion portion of the second-type battery pack when the second-type battery pack is inserted in the battery pack socket, and the battery pack socket has a shape that does not allow insertion of either the insertion portion of the first-type battery pack or the insertion portion of the second-type battery pack into the battery pack socket in any attitude other than the respective prescribed attitudes of the first-type battery pack and the second battery pack; a charging control unit housed in the housing; and at least a pair of output terminals disposed in the battery pack socket, wherein the pair of output terminals is electrically connected to the first-type battery pack when the insertion portion of the first-type battery pack in the prescribed attitude is inserted into the battery pack socket, and the pair of output terminals is electrically connected to the second-type battery pack when the insertion portion of the second-type battery pack in the prescribed attitude is inserted into the battery pack socket.