Cordless electric hand-tool with battery voltage safeguard

摘要

The handle of the tool (1) incorporates a recess (2) of appropriate size and shape for insertion of a battery pack (3) which has contacts (6) on a carrier (5) corresp. to the contacts (7) on the inside of the recess. To ensure correct alignment of contacts, a shallow slot (9) is provided in the rim (12) of the battery pack to match the projection (10) from the rim (11) of the recess. The position and size of the slot are related uniquely to the battery voltage so that the tool drive motor is protected against overvoltage from an unsuitable battery.