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US 2006/0220605 A1Published application
Cordless power tool with overcurrent protection circuit
AssigneeHitachi Koki Co., Ltd.
InventorsKazuhiko Funabashi, Takao Aradachi, Hiroyuki Hanawa, Masayuki Ogura
Life of this patent
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Abstract
A cordless power tool uses a lithium battery as a power source of a motor and is provided with an overcurrent protection circuit. The circuit allows an overcurrent to instantaneously flow at the start-up time of the motor and shuts off an overcurrent which may flow when the motor is brought into a locked state during the use of the power tool.
Claims17
A power tool comprising:
- a battery composed of a plurality of lithium battery cells connected in series;
- and
- a DC motor connected to the battery and supplied with a driving current from the battery,
- wherein an overcurrent defined by a current having a value equal to or greater than a predetermined value is prohibited to flow in the current path for more than a predetermined time period.
1 more element
A battery pack for use in a power tool including a motor, comprising:
- a battery composed of a plurality of lithium battery cells connected in series;
- and
- a pair of connection terminals for connection to the power tool;
- wherein an overcurrent defined by a current having a value equal to or greater than a predetermined value is prohibited to flow from the battery to the motor for more than a predetermined time period.
1 more element
Dependencies are inferred from the claim text.