Power tool with a DC brush motor and with a second power source
AssigneeJohnson Electric S.A.
InventorsJames Ching Sik Lau, Chang Lin Jin
Life of this patent
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Abstract
A power tool comprises a housing, a direct current motor arranged in the housing, a speed reduction mechanism coupled to a shaft of the motor, a tool head driven by the speed reduction mechanism, a first direct current power source, and a switching device. The motor comprises a common brush, a high speed brush and a low speed brush which are in sliding contact with a commutator. The switching device is configured to selectively connect the common brush and the high speed brush with the power source to operate the motor in a high speed mode and to connect the common brush and the low speed brush with the power source to operate the motor in a low speed mode.
Claims7
A power tool comprising:
- a housing, a direct current motor arranged in the housing, a speed reduction mechanism coupled to a shaft of the motor, a tool head driven by the speed reduction mechanism, a first direct current power source, a second direct current power source and a switching device,
- wherein the motor comprises:
- a common brush, a high speed brush and a low speed brush which are in sliding contact with a commutator;
- and
- wherein the switching device is configured to selectively connect the common brush and the high speed brush and the common brush and the low speed brush with predetermined combinations of the power sources to operate the motor in different speed modes.
Dependencies are inferred from the claim text.