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US 8,943,937 B2Granted
Power tool with circuit for sensing contact between an implement and an object
AssigneeRobert Bosch GmbH
InventorsArindam Haldar, Bharadwaja Maharshi Ramaswamy, Niranjan Sathyanarayanarao Krishnarao
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Abstract
A power tool includes a sensing circuit mounted on a printed circuit card is electrically connected to a switching power supply that supplies electrical power to the sensing circuit. The sensing circuit is not connected to earth ground to enable detection of an operator approaching a moving implement without the operator necessarily being electrically connected to earth ground.
Claims5
A power tool that moves an implement comprising:
- a terminal configured to receive an alternating current (AC) from an AC current source, which is electrically connected to earth ground;
- an implement configured for movement;
- an actuator operatively connected to the implement and electrically connected to the terminal to enable the actuator to operate and move the implement;
- and
- a printed circuit card to which a sensing circuit and a switching power supply are mounted, the switching power supply being electrically connected to the terminal to receive the AC current and being configured to generate electrical power for distribution to components on the printed circuit card, and the sensing circuit being electrically connected to the switching power supply to receive the electrical power and being configured to generate a sensing current that is electrically coupled to the implement, the printed circuit card being electrically connected to signal ground, but not electrically connected to earth ground to enable the sensing circuit to detect discharge of the sensing current to an object by the implement.
2 more elements
Dependencies are inferred from the claim text.