Electric power tool system

#This application claims priority to Japanese Patent Application No. 2010-241479 filed on Oct. 27, 2010 and Japanese Patent Application No. 2011-048918 filed on Mar. 7, 2011, the contents of which are hereby incorporated by reference into the present application.

#The present disclosure relates to electric (cordless) power tool systems that use a battery pack as a power source.

#A well known type of electric (cordless) power tool system is disclosed in WO 2006/044693 A2. This electric power tool system comprises a tool main body, a battery pack detachably attached to the tool main body, and a charger for charging the battery pack.

#FIG. 1 shows a tool main body, a battery pack, and a cordless charger of an electric power tool system according to Embodiment 1 of the present teachings.

#FIG. 2 shows an AC charger configured to charge the cordless charger of Embodiment 1.

#FIG. 3 is a block diagram that shows the construction and functional elements of the electric power tool system of Embodiment 1. In this drawing, connections shown with broken lines indicate detachable attachments between components, and the arrows show the direction of the current flow.

#In one embodiment of the present teachings, the first charger preferably includes a first unit, and a second unit detachably attached to the first unit. Preferably, the first unit houses the rechargeable battery, and the second unit includes an interface configured to attach to the battery pack. With such a construction, a great number of charges can be performed by providing a plurality of first units and using these in series. By sharing the second unit with the plurality of first units, the construction of the overall system can be simplified.

#In the aforementioned embodiment, it is preferable that the second unit also includes an interface configured to attach to the tool main body, and is electrically interposed between the tool main body and the battery pack. In this embodiment, the electric current output from the battery pack will be supplied to the tool main body via the second unit when the electric power tool is used. When the battery pack is to be charged, the charging current from the first unit will be supplied to the battery pack via the second unit.

#In addition or in the alternative, the first charger is preferably capable of charging the battery pack while the battery pack is attached to the tool main body. With such a construction, there is no need to remove the battery pack from the tool main body when the battery pack requires charging. The user can thus easily charge the battery pack between power tool operations.