Abstract: A reference voltage generator circuit includes: a first transistor and a second transistor, wherein the first transistor and the second transistor are coupled with each other and are located on a substrate, wherein the first transistor has a first conduction threshold voltage and a first rated voltage, wherein the second transistor has a second conduction threshold voltage and a second rated voltage, wherein the first rated voltage is higher than the second rated voltage; wherein the reference voltage generator circuit is configured to generate a bandgap reference voltage with temperature compensation according to a difference between the first conduction threshold voltage and the second conduction threshold voltage.

Abstract: A clutch device for a power tool includes a case in which a washer, a clutch, a clutch ring, planet gears and a sun gear are installed. The washer is connected with pins to which springs are respectively mounted. When switching and setting the torque by rotating the torque member, the pins do not extend through the clutch. The output torque of the tool is smaller than the input torque of the main shaft, the clutch ring is rotated by the sun gear and the planet gears. The ratchet teeth of the clutch ring are disengaged from the clutch teeth of the clutch. When switching to the drill mode, the pins extend through the clutch and contact with the clutch ring, the motor activates the gear box. Because the clutch ring is fixed by the pins and cannot rotate, the gear box outputs the maximum torque to drill objects.

Abstract: A power tool includes a variable speed device which can be set in an auto mode or a manual mode. The power tool does not need the user to set the speed when it is operated at the auto mode. The power tool is reset to be the high-speed mode when it is activated. The speed is reduced along with the working load so as to output high torque, maintain the best working efficiency and protect the power tool under the operative status. The power tool can be set to the manual mode so as to work in a single type of function.

Abstract: A multi-speed gear system for a power tool includes a case, a lever, a gear disk, a movable member, a ring gear, a planet gear unit and an idle gear unit. The movable member is axially moved to be engaged with the ring gear, the planet gear unit or the idle gear unit to change the gear ratios and output different speeds. The parts that are engaged with the movable member are located outside of the area where the gears are located, so that the switching between the speeds is smooth and has less friction.

Abstract: A clutch device for a power tool includes a case in which a washer, a clutch, a clutch ring, planet gears and a sun gear are installed. The washer is connected with pins to which springs are respectively mounted. When switching and setting the torque by rotating the torque member, the pins do not extend through the clutch. The output torque of the tool is smaller than the input torque of the main shaft, the clutch ring is rotated by the sun gear and the planet gears. The ratchet teeth of the clutch ring are disengaged from the clutch teeth of the clutch. When switching to the drill mode, the pins extend through the clutch and contact with the clutch ring, the motor activates the gear box. Because the clutch ring is fixed by the pins and cannot rotate, the gear box outputs the maximum torque to drill objects.

Abstract: A multi-gear mechanism includes first and second gear sets, an output set, multiple first planet gears pivotably connected between the first and second gear sets, a first gear ring having internal teeth and external teeth, multiple second planet gears cooperated with the internal teeth of the first gear ring, a second gear ring having internal teeth and side teeth, an operation gear ring and a motor gear. The motor gear extends through two central holes of the first and second gear sets, and the first and second planet gears are engaged with the motor gear. The operation gear ring is connected with the second gear ring which drives the operation gear ring to move axially. The motor gear drives the output set at low speed, constant speed or high speed when the operation gear ring and the second gear ring are operated to engage with different gears.

Abstract: An output mode switching device includes an output unit, a stationary ratchet gear unit, a spring, at least one block, a case for accommodating the parts mentioned above, and a control device threadedly connected to the case. The output unit includes an output shaft and a first bearing and a movable ratchet gear connected thereto. Movable ratchet teeth of the movable ratchet gear face stationary ratchet teeth of the stationary ratchet gear. The stationary ratchet gear has circumferential ribs and the block has an inner protrusion and an outer protrusion. Two ends of the spring respectively contact with the first bearing and the inner protrusion of the block. The control device is operated to allow the inner protrusion to be engaged with or separated from the rib of the stationary ratchet gear. Therefore the output shaft outputs torque without axial vibration or with axial vibration.

Abstract: A gapless main shaft locking apparatus includes a fastening ring, an elastic retaining device, a plurality of detent pins, a driving plate and an output shaft. The elastic retaining device is installed in the fastening ring and has an inner space in which elastic portions and cylinder portions are disposed. Each of the detent pins is disposed between one of the elastic portions and one of the cylinder portions. The driving plate has a central hole, and the periphery of the central hole includes fan-shaped convex portions. A side of the driving plate has a plurality of concave slots for receiving the elastic retaining device. The output shaft includes a polygonal shaft having a regular polygonal cross section. The polygonal shaft passes through the central hole of the driving plate, and each side of the polygonal shaft is contacted with one of the detent pins.

Abstract: An output mode switching apparatus including a power unit, a hammering unit, an output shaft, a housing, and a shifting member is provided. The hammering unit includes a gasket cup, a switching ring, a spring member, a hammering seat, and a main shaft. When the power unit is not in operation, the switching ring is restricted so as to be positioned against and secured to the gasket cup. When the mains shaft is driven by the power unit to rotate, the hammering seat is carried to rotate and is applied with a restriction for restricting the hammering seat from axial movement, thus configuring an output mode of electric drill. When the shifting member is turned, the restriction applied to the hammering seat is released. The hammering blocks repetitively hammers the protrusion blocks and axially returns back to the original position, thus configuring an impact output mode.

Abstract: A main shaft locking mechanism includes a fixing ring, a main shaft and detents. The main shaft includes an equilateral portion that has an equilateral cross section. A number of the corners of the equilateral portion is equal to that of the detents. The detent has an exterior side and an interior side opposite to the exterior side. The interior side includes two corner protrusions protruded out from two ends thereof and a concave portion defined between the two corner protrusions. The corners of the main shaft are received in the concave portions of the detents. When the main shaft is manually driven to rotate, the corners of the main shaft drive the detents to deviate. Therefore, the exterior sides of the detents interfere against the fixing ring. Then the detents prevent the main shaft from further rotating, thus locking up the main shaft.

Abstract: A multi-gear mechanism includes first and second gear sets, an output set, multiple first planet gears pivotably connected between the first and second gear sets, a first gear ring having internal teeth and external teeth, multiple second planet gears cooperated with the internal teeth of the first gear ring, a second gear ring having internal teeth and side teeth, an operation gear ring and a motor gear. The motor gear extends through two central holes of the first and second gear sets, and the first and second planet gears are engaged with the motor gear. The operation gear ring is connected with the second gear ring which drives the operation gear ring to move axially. The motor gear drives the output set at low speed, constant speed or high speed when the operation gear ring and the second gear ring are operated to engage with different gears.

Abstract: A main shaft locking mechanism includes a fixing ring, a main shaft and detents. The main shaft includes an equilateral portion that has an equilateral cross section. A number of the corners of the equilateral portion is equal to that of the detents. The detent has an exterior side and an interior side opposite to the exterior side. The interior side includes two corner protrusions protruded out from two ends thereof and a concave portion defined between the two corner protrusions. The corners of the main shaft are received in the concave portions of the detents. When the main shaft is manually driven to rotate, the corners of the main shaft drive the detents to deviate. Therefore, the exterior sides of the detents interfere against the fixing ring. Then the detents prevent the main shaft from further rotating, thus locking up the main shaft.

Abstract: An output mode switching apparatus including a power unit, a hammering unit, an output shaft, a housing, and a shifting member is provided. The hammering unit includes a gasket cup, a switching ring, a spring member, a hammering seat, and a main shaft. When the power unit is not in operation, the switching ring is restricted so as to be positioned against and secured to the gasket cup. When the mains shaft is driven by the power unit to rotate, the hammering seat is carried to rotate and is applied with a restriction for restricting the hammering seat from axial movement, thus configuring an output mode of electric drill. When the shifting member is turned, the restriction applied to the hammering seat is released. The hammering blocks repetitively hammers the protrusion blocks and axially returns back to the original position, thus configuring an impact output mode.

Abstract: A power output mechanism for power tools includes a main part for driving an output shaft, a switch unit, an impact unit, a pressing unit, and an operation member. The switch unit has a rotation collar for controlling positions of positioning springs. The impact unit includes an orientation wheel movably connected to the output shaft and an operation wheel secured to the output shaft. The orientation wheel includes a first toothed contact surface which is removably engaged with a second toothed contact surface of the operation wheel. A corrugated ring portion is defined on an outer periphery of the orientation wheel and limited from rotation relative to the output shaft when the positioning springs are moved to certain positions. When the positioning springs are engaged with the orientation wheel, the orientation wheel cannot freely rotate relative to the output shaft so that an impact is output.

Abstract: A power output mechanism for power tools includes a main part for driving an output shaft, a switch unit, an impact unit, a pressing unit, and an operation member. The switch unit has a rotation collar for controlling positions of positioning springs. The impact unit includes an orientation wheel movably connected to the output shaft and an operation wheel secured to the output shaft. The orientation wheel includes a first toothed contact surface which is removably engaged with a second toothed contact surface of the operation wheel. A corrugated ring portion is defined on an outer periphery of the orientation wheel and limited from rotation relative to the output shaft when the positioning springs are moved to certain positions. When the positioning springs are engaged with the orientation wheel, the orientation wheel cannot freely rotate relative to the output shaft so that an impact is output.

Abstract: A protection device for a speed shifting mechanism includes a case with a gear reduction unit received therein, and a tube is rotatably mounted to the case. The tube includes a plurality of positioning notches and a guide groove. A button mechanism includes an activation rod which is connected to the gear reduction unit and a shifter is connected to the activation rod. The shifter is engaged with the guide groove and a button is secured on the shifter. A control member includes a positioning plate which has a protrusion. The shifter is moved by operation of the button and the tube is rotated along with the movement of the shifter. When the protrusion is engaged with one of the positioning notches, the tube is locked and cannot rotate such that the shifter cannot be shifted unintentionally.

Abstract: A locking device includes an outer ring in which a clutch disc and a locking disc are respectively connected at two opposite sides thereof A first pad is located on clutch disc and a second pad is located on the first pad. A plurality of balls are located between adjacent first and second protrusions of the first and second pads. A plurality of springs are biased between the far first and second protrusions. A screw bolt connected with a grinding wheel is threadedly extended through the locking disc. When the outer ring is rotated in first direction, the balls do not fall into the recesses defined in the locking disc so as to push the clutch disc to lock the grinding wheel. When the outer ring is rotated in second direction, the balls fall into the recesses and the clutch disc is loosened from the grinding wheel.

Abstract: A switching device for an impact power tool includes an input unit, a clutch unit, an output unit and a spring. The clutch unit is cooperated with the spring and located between the input unit and the output unit. The clutch unit includes a clutch disc connected to an input shaft of the input unit and a collar. The output unit includes an output shaft with struck blocks and a pounding member with striking blocks. When the collar is moved and connected with the clutch disc, the input shaft, the pounding member, the collar and the output shaft rotate simultaneously. The output shaft outputs rotation only. When the collar is moved and disengaged from the clutch disc, the input shaft drives the pounding member and the pounding member drives the output shaft to rotate. The output shaft outputs rotation with impact intermittently.

Abstract: An impact power tool includes a motor, a first planetary gear set, a clutch having a sun gear, a second planetary gear set, a transmission shaft, an intermediate shaft, an impact seat and an output shaft. When the clutch moves to a first position, the transmission shaft engages with a second planet carrier of the second planetary gear set and the output shaft. The power of the motor is transmitted to the output shaft via the first planetary gear set, the second planetary gear set, and the transmission shaft in low-speed mode. When the clutch moves to a second position, the transmission shaft disengages from the second planet carrier and the output shaft. The power of the motor is output to the output shaft via the first planetary gear set, the second planetary gear set, the transmission shaft, the intermediate shaft, and the impact seat in high-speed-with-impact mode.

Abstract: A transmission mechanism includes a motor, a first planetary gear set, a clutch connected with a sun gear, a second planetary gear set, a transmission shaft, an intermediate shaft and an output shaft. When the clutch is moved to the first position, the transmission shaft engages with the second planetary gear set and the output shaft, such that the power can be transmitted to the output shaft via the first planetary gear set, the second planetary gear set and the transmission shaft. When the clutch is moved to the second position, the transmission shaft disengages from the second planetary gear set and the output shaft, such that the power can be transmitted to the output shaft via the first planetary gear set, the second planetary gear set, the transmission shaft and the intermediate shaft.