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: A stand mixer having an electrical speed control circuit for providing a temporary incremental power burst to the motor of the mixer.

Abstract: A cooling system for cooling components of a computer is provided. The cooling system includes a DC fan which operates at a speed which is substantially proportional to the voltage that is applied to the fan. A zener diode voltage divider is connected in series between a voltage source and a first input of the fan. The second input of the fan is connected to a reference voltage source. A switch is also connected in series between the voltage source and the first voltage input of the fan so as to be connected in parallel with the zener diode voltage divider. When the switch is in a first position, the voltage produced by the voltage source is applied directly to the fan allowing the fan to operate at a first speed. When the switch is in a second position, the voltage from the voltage source is applied to the first input of the fan through the zener diode such that the first input of the fan receives a second voltage that is less than the first voltage thereby causing the fan to operate at a second speed.

Abstract: The invention concerns an electromechanical device with variable resistance circuit serving to control a load. The device comprises a connection (10) for a source of power (12), a connection (14) apt to be connected to a load (16) supplied by the source of power (12), a resistance circuit formed by a plurality of branches (B.sub.1, B.sub.2, . . . B.sub.n) mounted in parallel between the connections (10, 14) and each comprising a resistance (R.sub.1, R.sub.2 . . . R.sub.n) in series with a switch (I.sub.1, I.sub.2, . . . I.sub.n) possessing an initial contact state and mechanical means comprising a carriage (20) moveable in translation between several predetermined positions, in each of which this carriage (20) is apt to co-operate with at least one of the switches (I.sub.1, I.sub.2, . . . I.sub.n) in order to modify its initial contact state and vary the intensity of the current traversing the load.

Abstract: An adjustable speed control for use on a children's ride-on vehicle, where the speed control includes a switch assembly interposed between the battery and the motor of the vehicle. The switch assembly is selectively operable to connect the battery to the motor in one of a number of speed configurations, including a first speed configuration and a second speed configuration. An actuator is connected to the switch assembly and manipulable by a user to allow the user to operate the switch assembly to select a particular speed configuration from among the number of speed configurations. In one embodiment, a diode is disposed in series between the motor and battery in one of the speed configurations to provide a relatively current independent voltage drop between the motor and the battery. In an alternative embodiment, a childproof cover is disposed proximal to the actuator.

Abstract: A system for enabling a vehicle operator to control the speed or rate of raising and lowering of a powered lift window. The actuator or switch includes a pressure responsive variable impedance device comprising a variable resistance in one embodiment and a variable capacitance in another embodiment. Increasing force directly on the variable impedance device by the user's finger or an actuator decreases the impedance which is sensed by a voltage divider which outputs a voltage which increases with increasing force. This latter voltage is compared with the output of a triangle wave oscillator and the output of the comparator is a pulse width modulated signal with pulse-width proportional to applied force. The pulses are applied to a power device (Mosfet) which modulates the duty cycle (%) of the current to the window lift mechanism drive motor to give variable motor speed.

Abstract: The present invention provides the following rotation control method for reducing energy consumption of a motor driving a disk. In a constant speed mode, a supply voltage V1 for driving the motor at a constant speed N1 is selected; however, at a lower constant speed N2, a supply voltage V2 lower than V1 is selected. In an acceleration mode for accelerating the motor speed from N2 to N1, a higher supply voltage than V1 is selected just before starting acceleration, and then V1 is selected after the acceleration. In a speed deceleration mode for decelerating the motor speed from N1 to N2, a lower supply voltage than V1 is selected just before starting deceleration, then the supply voltage V2 is selected after the decleration.

Abstract: A simple speed controller for small direct current motors having a hollow body with a joystick extending out from the body. Within the housing the two facing side walls have nonconductive substrates with conductive traces. Transistors are connected to both substrates and the joystick has conductors to act as wipers for potentiometers which act to control the speed of the motor.

Abstract: A switching arrangement for controlling the rpm constancy between idling and full power of universal motors in electric tools has a phase-shift control (IC) which, for setting the set value, is connected at an output via an adjusting resistor with a tap of a voltage divider, and whose trigger output controls an electronic power switch disposed in the electrical circuit of the motor. In order to obtain an optimal readjustment of the load in the entire provided rpm range by means of such a switching arrangement, it is provided that between the tap of the voltage divider and the one output of the phase-control circuit (IC) at least one further adjusting resistor is provided, with which a preferably electronic circuit device is switched in parallel, which is controlled from a point in the voltage divider.

Abstract: A DC motor control circuit for controlling a restraint torque of a DC motor which continues the rotation by triggering an external force. This control circuit is installed in a DC motor. In a DC motor control circuit comprising a drive transistor collector connected to a first brush of a DC motor, and a detection transistor collector connected to the base of said drive transistor and base connected to said first brush, a variable resistor is connected between the emitter of said detection transistor and a second brush of said DC motor and a capacitor connected between their one end and movable terminal of said variable resistor. The control circuit further comprises a drive current limiter for the drive transistor.

Abstract: A DC motor control system reduces power demands imposed upon a DC power source energizing a utilizing device by varying the time during which power application occurs, but not the magnitude of the power which remains constant. The DC motor control system includes a transducer/resistor network, a trigger pulse circuit, a control signal circuit, a driver circuit, and a switch network. The control signal circuit outputs a duty cycle control signal as regulated by the transducer/resistor network and the trigger pulse circuit. The transducer/resistor network permits an operator to determine the duration of the duty cycle control signal, which varies from 0% to 100%, while the trigger pulse circuit establishes the frequency of the duty cycle control signal. The driver circuit receives and amplifies each duty cycle control signal outputted by the control signal circuit. The driver circuit inputs each amplified duty cycle control signal into the switch network to activate it.

Abstract: A speed servo-control apparatus is provided for use in combination with a walking-running exercise machine including a moving belt on which a user may walk or run and a direct current drive input for controlling the speed of the moving belt. The apparatus has a frame bracket and a control unit rotatably mounted to the frame bracket, and is provided with an assembly for mounting the frame bracket at a predetermined position with respect to the machine. The apparatus is also provided with a cord assembly having two opposite extremities, one of the extremities being operatively connected to the control unit and the other of the extremities being attachable to the user of the apparatus so as to rotate the control unit in a given direction when the cord assembly is pulled forward.

Abstract: A speed control mechanism allowing a user to control the operating speed of a power tool. The speed control mechanism includes a drive motor and a handle connected to the power tool including a trigger, a speed governor and a cam assembly. The trigger is displaced from a first position by the user to initiate operation of the drive motor. The trigger cooperates with the speed governor to vary the operating speed of the drive motor based on the displacement of the trigger. The cam control assembly is operated by the user and cooperates with the trigger to control the extent to which the trigger can be displaced from the first position by the user, thereby limiting the operating speed of the motor. In one embodiment, the speed control mechanism is for use with the drive motor of the power tool to control the operating speed of the power tool. In an alternative embodiment, the speed control mechanism is used with a radial arm saw including an anti-kick forward device.

Abstract: The present invention is a two unit electronic control system to reduce power demands imposed upon direct current power sources. The present invention comprises a contact/resistor network, a trigger generator, a pulse generator, a waveform stabilization circuit, a driver circuit, a voltage regulation circuit, a noise suppression circuit, a transient suppression circuit, a field effect transistor network and primary and secondary on/off control circuits. The input can be resistance, voltage, current or capacitance which is varied in response to an external stimulus. The chosen input is conditioned and applied to vary the duty cycle of a repeating pulse signal. That pulse signal is conditioned and applied to a switching device which controls the current from the DC power source to the load. The number of switching devices comprising the network will vary from one to many dependent upon the current carrying demand of the load and the current handling capability of the switching device utilized.

Abstract: A method for controlling the speed of rotation of a motor by changing the resistance value of a resistor circuit connected in series to the motor and having discontinuous resistance values, including the steps of applying voltage across the motor. Detecting when the applied voltage is lower than a first applied voltage and the resistance value of the resistor circuit is a first resistance value and changing the resistance value of the resistor circuit over to a second resistance value lower than the first resistance value. Detecting when the applied voltage detected is higher than a second applied voltage higher than the first applied voltage and the resistance value of the resistor value is the second resistance value and changing the resistance value of the resistor circuit over to the first resistance value.

Abstract: The invention relates to an electric propulsion system for a multi-wheeled vehicle including though not limited to a bicycle. The preferred embodiment consists of a standard street bicycle with multi-speed transmission, plus an electrical propulsion system and a solar charging apparatus. This preferred embodiment is normally powered by a combination of motor and pedals, coupled such that either or both may provide power at any time.

Abstract: A variable resistance switch includes first and second flexible contact arms engageable by a pair of cam followers operable sequentially by an actuator movable in a first and an opposite direction. The actuator also carries a wiper movable therewith over a variable resistance coupled to a terminal. The first contact arm is operable upon initial movement of the actuator in a first direction to complete a first circuit through the switch, and the second switch arm is operable upon further movement of the actuator in the first direction to complete a second circuit through the switch and to place the variable resistance in circuit between one of the switch arms and the terminal. Further movement of the actuator in the first direction is operable to move a wiper over the resistance to vary the resistance in circuit with the terminal. A pivotal trigger is coupled to the actuator for moving the same in the first direction, and a spring biases the cam in the opposite direction.

Abstract: In this control circuit for a DC motor, there are provided: a device which generates a triangular voltage wave; a device which generates a variable reference voltage; a device which compares the voltage from the triangular voltage wave generator and the voltage from the variable reference voltage generator, and produces a speed variation control output according to the result of this comparison; and a device which controls the supply of electric current to the DC motor according to the thus produced speed variation control output. Optionally, control power source lines from the device for controlling the supply of electric current to the DC motor are connected to the two ends of an armature of the DC motor. By this simple construction the number of parts of the control circuit is minimized, and the construction is made compact, light, and cheap.

Abstract: A remote-control system is used in combination with a sewing machine for controlling revolution of a sewing machine motor. A remote-controller is connected to a main body of the sewing machine and operated by the sewing machine operator to change a resistance value of a variable resistor contained therein so that the sewing machine motor is driven under control in response to an output volume from the variable resistor. A condensor is connected to said variable resistor and chargeable by a power supply source mounted in the sewing machine main body. The output voltage is converted into a corresponding digital value at each timing when the condensor is saturated with electricity in response to a clock pulse signal at a predetermined interval. The output voltage at such timing will be in proportion to the resistance value of the variable resistor which is, in turn, in porportion to the amount of operation of the remote-controller.

Abstract: An electric switch system for a DC motor powered power tool, comprising: a moveable block which is adapted to be manually displaced between a first position and a second position for speed control of the motor; a fixed block arranged adjacent to the first moveable block; a manual selection lever pivotally attached to the fixed block and adapted to be manually rotated from a neutral middle position to either side for the selection of the rotational direction of the motor; a cam structure for permitting the manual rotation of the manual selection lever in either direction away from the middle neutral position only when the moveable block is at the first position and keeping the angularly displaced state of the manual selection lever when the moveable block is displaced away from the first position. Thus, the selection of the rotational direction of the motor and the speed control of the motor can be accomplished as a continuous single operation, and the convenience of the power tool is improved.