Abstract: A switching circuit for varying rotational speed of a motor includes a power supply line for connecting the motor to a power source so as to supply driving power to the motor. A parallel connecting circuit of an on-off switch and a short circuiting switch is provided in the power supply line, in such a manner that the driving power is continuously supplied to the motor when the short circuiting switch is on, while in the case that the short circuiting switch is off, the driving power is supplied to the motor during on of the on-off switch but is not supplied during off of the on-off switch. A control member is provided for operation by an operator for varying rotational speed of the motor. The control member is operative for turning on the short circuiting switch at the maximum amount of its operation.
Type:
Grant
Filed:
April 24, 1990
Date of Patent:
December 11, 1990
Assignees:
Makita Electric Works, Ltd., Omron Corporation
Abstract: A portable reciprocating saw includes a tool housing, an electric motor enclosed in the tool housing and having an output shaft, an elongated slider for supporting a saw blade, and motion converting means mounted in the tool housing for converting the rotation from the electric motor into a reciprocating motion of the slider in longitudinal direction. The motion converting means includes a bevel gear meshing with the ouptut shaft of the electric motor and rotatable about an axis inclined to a plane transverse to the longitudinal direction of the slider, a slider block mounted on the slider and having a guide groove formed on a lower surface thereof in a direction transverse to the longitudinal direction of the slider, and an eccentric pin mounted on the bevel gear at a position eccentric from the center of the bevel gear and loosely fitted in the guide groove of the slider block.
Abstract: A combined locking mechanism and switch especially for power tools has a switch, an actuator for directly turning on or off the switch, a locking member shiftable between a first position in which it is disposed in opposed relation to the actuator and a second position in which it is spaced apart form the actuator, and an actuating member for actuating the actuator through the locking member only when the locking member is placed in the first position.
Type:
Grant
Filed:
March 24, 1989
Date of Patent:
June 19, 1990
Assignees:
Makita Electric Works, Ltd., Omron Tateisi Electronics Co.
Abstract: A portable, cordless battery-powered tool with a relatively small overall length is provided. A handle section forms the rearmost part of the tool. An electric motor is located below a spindle and forwardly of the handle section. The motor has a rotatable shaft located in parallel with the spindle. The handle section is provided with a switch trigger which is substantially aligned with the central axis of the spindle at its top.
Abstract: An electric motor includes a commutator and a brush assembly. The brush assembly includes a pair of brushes, each disposed in operative relation to the commutator, a pair of brush holders each supporting at least one of the brushes, and an assembly base (69, 74) for securing the brush holders thereto. The assembly base includes a base plate of insulating material and at least two severable conductive passages (71, 72) each secured to the base plate. The conductive passages are adapted to supply electric current to the pair of brushes from different directions and drive the electric motor for rotation in either forward or reverse direction when either one of the passages is severed for permitting use of a single brush assembly in different kinds of motors.
Type:
Grant
Filed:
December 21, 1988
Date of Patent:
May 15, 1990
Assignee:
Makita Electric Works, Ltd.
Inventors:
Fusao Fushiya, Kenji Yoshida, Akira Naitoh, Tetsuya Sawa
Abstract: A portable circular saw includes a housing having an electric motor mounted therein. A circular saw blade is attached to the housing and is adapted to be driven by the electric motor. A handle is carried by the housing. A base plate is disposed below the housing and has an opening therein for receiving substantially the lower half of the saw blade. Support means is mounted on the front end of the base plate for supporting the housing for pivotal movement relative to the base plate, and has a stand portion disposed in laterally spaced apart aligned relation to the front end of the base plate. Thus, the circular saw may be rested in an upright position by the front end of the base plate and the stand portion of the support means.
Abstract: A brush holder assembly for a commutator type electric motor includes a substantially circular base plate of insulating material having a central aperture for receiving the motor commutator. The base plate includes a pair of brush holders for supporting brushes in operative relation to the commutator. A pair of conductive members are embedded in the base plate. Each conductive member has a brush holder mounting portion exposed on both sides of the base plate and a connecting terminal for electrical connection to the corresponding terminal of the stator coils. Power connecting means is provided on the base plate for electrically connecting the terminals of the stator coils to an electrical power source.