Abstract: An electric motor has a pair of brushes for transferring power to windings of a wound rotor by making sliding contact with a cylindrical commutator. Each brush has a body with a pair of end surfaces, and a contact surface extending between the end surfaces and configured to slidingly contact a cylindrical circumferential surface of the commutator. The extending direction of the contact surface is inclined relative to the axial direction of the commutator, and the contact surface is V-shaped when viewed in the extending direction thereof.

Abstract: A direct current motor includes a stator and a rotor. The rotor has a shaft; a rotor core fixed to the shaft; a commutator fixed to the shaft; and rotor windings wound about poles of the rotor core and terminated on the commutator. The motor also has a common brush and at least two selectable brushes in sliding contact with the commutator; at least two direct current power sources; and a switching device configured to connect the common brush and a selected one of the selectable brushes with predetermined combinations of the power sources to operate the motor in different speed modes.

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.

Abstract: Brush gear of a motor has a brush card with a plurality of brushes installed at one side thereof. Each brush is electrically connected with a connector. Two motor terminations provide power to the brushes via the corresponding connectors and at least one wire connects two of the connectors. Each of said two of the connectors has a hole to receive one end of the wire and at least two fingers extends from an edge of the hole inclined toward the axis of the hole, such that when the end of the wire extends through the hole, the fingers are resiliently deformed and grip the wire to prevent withdrawal of the wire from the hole.

Abstract: An electric motor includes: a rotor; a stator; and brush gear. The rotor has a shaft, a rotor core and a commutator fitted to the shaft. The rotor core has 5n teeth, n being a positive integer. Two coils are wound on each tooth with each coil being wound about a single tooth and having two ends. The commutator has 10n bars forming a brush contact surface. The stator includes a yoke and a plurality of permanent magnets installed at an inner surface of the yoke and facing the rotor core. The ends of the two coils wound on each tooth are respectively connected to two pairs of adjacent bars and the center line between one pair of the two pairs of adjacent bars and the center line between the other pair of the two pairs of adjacent bars are diametrically opposed.

Abstract: A multi-pole PMDC motor has brush gear for transferring electrical power from motor terminations to its windings via a commutator. The brush gear comprises a brush card supporting at least four brush assemblies. The brush assemblies are separated into two brush groups with the brush assemblies of each group being electrically connected together by links of flexible wire.

Abstract: A direct current motor comprising a stator and a rotor. The rotor comprises: a shaft; a rotor core fixed to the shaft; a commutator fixed to the shaft; and rotor windings wound about poles of the rotor core and terminated on the commutator. The motor also has a common brush and at least two selectable brushes in sliding contact with the commutator; at least two direct current power sources; and a switching device configured to connect the common brush and a selected one of the selectable brushes with predetermined combinations of the power sources to operate the motor in different speed modes.

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.

Abstract: An electric motor has a pair of brushes for transferring power to windings of a wound rotor by making sliding contact with a cylindrical commutator. Each brush has a body with a pair of end surfaces, and a contact surface extending between the end surfaces and configured to slidingly contact a cylindrical circumferential surface of the commutator. The extending direction of the contact surface is inclined relative to the axial direction of the commutator, and the contact surface is V-shaped when viewed in the extending direction thereof.

Abstract: A power tool has a power head 11; a motor 10 configured to drive the power head; a handle 13 at which a switch 30 and a trigger 31 are installed; a force sensor 33 installed at the handle and electrically connected to the switch and configured to output voltage in response to force acted thereon; and a control unit configured to control the motor in response to the output voltage from the force sensor. A method for operating a power tool is also disclosed.

Abstract: A multi-pole PMDC motor has brush gear for transferring electrical power from motor terminations to its windings via a commutator. The brush gear comprises a brush card supporting at least four brush assemblies. The brush assemblies are separated into two brush groups with the brush assemblies of each group being electrically connected together by links of flexible wire.

Abstract: Brush gear of a motor has a brush card with a plurality of brushes installed at one side thereof. Each brush is electrically connected with a connector. Two motor terminations provide power to the brushes via the corresponding connectors and at least one wire connects two of the connectors. Each of said two of the connectors has a hole to receive one end of the wire and at least two fingers extends from an edge of the hole inclined toward the axis of the hole, such that when the end of the wire extends through the hole, the fingers are resiliently deformed and grip the wire to prevent withdrawal of the wire from the hole.

Abstract: An electric motor comprises: a rotor; a stator; and brush gear. The rotor has a shaft, a rotor core and a commutator fitted to the shaft. The rotor core has 5n teeth, n being a positive integer. Two coils are wound in each tooth with each coil being wound about a single tooth and having two ends. The commutator has 10n bars forming a brush contact surface. The stator comprises a yoke and a plurality of permanent magnets installed at an inner surface of the yoke and facing the rotor core. The brush gear has a plurality of carbon brushes arranged to make sliding contact with the brush contact surface of the commutator. The ends of the two coils wound in each tooth are respectively connected to two pairs of adjacent bars and the center line between one pair of the two pairs of adjacent bars and the center line between the other pair of the two pairs of adjacent bars are diametrically opposed.

Abstract: An electric drill has a handle, a body and a drill chuck. The handle is provided with a battery and a switch. The body comprising a shell, a motor fixed in the shell and an impeller fixed to an axle or shaft of the motor. The shell is provided with a plurality of air outlets at a position corresponding to the impeller, the impeller being able to rotate with the axle of the motor to produce an air current to cool the motor. An enclosure of the battery is provided with a plurality of through holes. An air current channel is formed inside the handle and the body and connected to the environment via the through holes of the battery enclosure. A heat dissipating device is located in the air current channel and contacts the switch. A part of the cooling air current passes through the air current channel to cool the battery before getting to the motor.

Abstract: Clocks are synchronized using a reference clock in two possible ways. One method uses two-way communication between a reference clock and a moving clock. The other method uses one-way communication from the moving clock.

Abstract: A lock has an outer housing, which has an outer slot at an interior side. An inner housing is received in the outer housing for rotation and has an inner slot and a driving section. Three locking plates are received in the inner housing, each of which has and a recesses at a periphery thereof. A movable pin is moved to be received either in the inner and outer slots or in the inner slot and the recesses. A first tumbler pin is provided at the outer housing and has an end received either in the annular slot or in the position slot. The inner housing is reciprocated between a first position, in which the position pin is moved to a position slot to restrain the inner housing from rotation, and a second position, in which the position pin is moved to an annular slot to release the inner housing.

Abstract: Clocks are synchronized using a reference clock in two possible ways. One method uses two-way communication between a reference clock and a moving clock. The other method uses one-way communication from the moving clock.

Abstract: Clocks are synchronized using a reference clock in two possible ways. One method uses two-way communication between a reference clock and a moving clock. The other method uses one-way communication from the moving clock.

Abstract: The nucleotide sequence is provided for a novel death regulatory gene. In particular the present invention relates to a DNA segment encoding a giig15b gene; polypeptides encoded by that DNA segment; recombinant DNA molecules containing the DNA segment; cells containing the recombinant DNA molecule; a method of producing a giig15b peptide; and antibodies specific to giig15b protein.