Abstract: A power tool includes a housing rotatably secured to a seat and having an internal gear and having a bore for rotatably receiving a driving shaft. A motor is secured to the seat and includes a spindle having a pinion engaged with the internal gear for driving the housing to rotate relative to the seat. A pawl is rotatably secured in the housing, and has two ends selectively engaged with the shaft to rotate the shaft in either direction when the housing is rotated relative to the seat by the motor with a speed greater enough to cause the pawl to engage with the shaft.

Abstract: An air compressor includes a base having an opening to receive a bearing, an eccentric member having a shaft rotatably secured to the base with the bearing and having an eccentric pin, and a cylinder having a piston rod rotatably coupling to the eccentric pin. A gear is attached to the eccentric member and rotated in concert with the eccentric member, and a motor is secured to the base and includes a pinion engaged with the gear to rotate the gear and the eccentric member relative to the base. The gear and the eccentric member may be rotated in great speeds by the motor, and may be stably and smoothly secured to the base with the bearing.

Abstract: A power tool includes a housing rotatably secured to a seat and having an internal gear and having a bore for rotatably receiving a driving shaft. A motor is secured to the seat and includes a spindle having a pinion engaged with the internal gear for driving the housing to rotate relative to the seat. A pawl is rotatably secured in the housing, and has two ends selectively engaged with the shaft to rotate the shaft in either direction when the housing is rotated relative to the seat by the motor with a speed greater enough to cause the pawl to engage with the shaft.

Abstract: An air compressor includes a cylinder housing having a passage formed in one end, a piston slidably received in the cylinder housing and moved relative to the cylinder housing in a reciprocating action to generate a pressurized air out through the passage of the cylinder housing. The cylinder housing includes an outlet tube having a bore communicating with the passage and the chamber of the cylinder housing, and having two or more ducts for readily coupling to and for supplying the pressurized air to the nozzle, the pressure gauge, the safety valve, or the other devices.

Abstract: An air compressor includes a cylinder attached to the base, two or more motors selectively secured to the base and each having a spindle extended through the base. The motors may include different driving powers or different diameters. Two coupling devices may couple the spindles of the motors to the cylinder respectively. A smaller motor includes a pinion secured to the spindle and engaged with a gear, and a weight is secured to the gear and coupled to the cylinder. The spindle of a greater motor may be secured to the weight which is then secured or coupled to the cylinder.

Abstract: An air compressor includes a cylinder attached to the base, two or more motors selectively secured to the base and each having a spindle extended through the base. The motors may include different driving powers or different diameters. Two coupling devices may couple the spindles of the motors to the cylinder respectively. A smaller motor includes a pinion secured to the spindle and engaged with a gear, and a weight is secured to the gear and coupled to the cylinder. The spindle of a greater motor may be secured to the weight which is then secured or coupled to the cylinder.

Abstract: A booster battery device includes one or more batteries disposed in a housing. Two arms are disposed on the sides of the housing and each having an upper stud and a lower rod and/or two middle bars secured to the housing, for forming a space between the arm and the stud and the rod and/or the bars. Two clips are electrically coupled to the battery with cables and each has two jaws for clasping onto the studs and for retaining the clips between the studs and the rods. The rods may retain the clips to the housing when the clips are disengaged from the studs inadvertently.

Abstract: An air compressor includes two housings secured to a base and each having a piston slidably received in the housings. A weight is rotatably secured to the base and includes an eccentric pin rotatably coupled to the piston rods for moving the pistons relative to the housings to conduct the pumping operations. A motor is secured to the base and has a pinion. A gear is rotatably secured to the base with the pivot shaft and engaged with the pinion and driven by the motor via the pinion. The housings may be adjustably secured to the base.

Abstract: A compressor includes a piston slidably received in a chamber of a housing and having an annular groove for receiving a sealing ring, and having one or more conduits and having a number of openings communicating with the annular groove of the piston. The piston includes an inclined peripheral surface having a lower diameter greater the sealing ring for forcing the sealing ring to engage with the housing, and having an upper diameter less than that of the sealing ring for loosely receiving the sealing ring. A spring blade may selectively block the conduits of the piston.

Abstract: A compressor includes a piston slidably received in a chamber of a housing and having an annular groove for receiving a sealing ring, and having one or more conduits and having a number of openings communicating with the annular groove of the piston. The piston includes an inclined peripheral surface having a lower diameter greater the sealing ring for forcing the sealing ring to engage with the housing, and having an upper diameter less than that of the sealing ring for loosely receiving the sealing ring. A spring blade may selectively block the conduits of the piston.

Abstract: An air compressor includes a bearing engaged in a base, a weight having a pivot axle rotatably and stably secured to the casing with the bearing and having a shaft offset or eccentric relative to the pivot axle. A cylinder includes a piston rod rotatably coupling to the shaft of the weight. A gear is engaged on the weight and rotated in concert with the weight relative to the base about the pivot axle. A motor is secured to the base and has a pinion engaged with the gear for rotating the weight and for moving the piston rod relative to the cylinder in a reciprocating action.

Abstract: An air compressor includes two housings secured to a base and each having a piston slidably received in the housings. A weight is rotatably secured to the base and includes an eccentric pin rotatably coupled to the piston rods for moving the pistons relative to the housings to conduct the pumping operations. A motor is secured to the base and has a pinion. A gear is rotatably secured to the base with the pivot shaft and engaged with the pinion and driven by the motor via the pinion. The housings may be adjustably secured to the base.

Abstract: An air compressor includes a housing having a port formed in a motor casing and another port formed in a fan casing. The fan casing has a mouth for air to flow into the housing. The mouth may be selectively blocked for facilitating the drawing of the air into the housing via the ports. The fan device includes a plate having two sides and having one or more blades extended from each of the sides of the plate for facilitating the air circulating or paddling or drawing effect of the air compressor. The blade is preferably extended radially and laterally relative to the plate.

Abstract: An air compressor includes a housing having a port formed in a motor casing and another port formed in a fan casing. The fan casing has a mouth for air to flow into the housing. The mouth may be selectively blocked for facilitating the drawing of the air into the housing via the ports. The fan device includes a plate having two sides and having one or more blades extended from each of the sides of the plate for facilitating the air circulating or paddling or drawing effect of the air compressor. The blade is preferably extended radially and laterally relative to the plate.

Abstract: An air compressor includes a pressure gage attached to a cylinder housing, a compression device having a piston container slidably received in the cylinder housing for supporting a compression valve and a positioning block and a valve piece and a limiting piece. A motor is secured to a seat. A gear is rotatably secured to the seat and driven by the motor and includes a weight pivotally coupled to the piston container with a link. The elements may be secured onto the cylinder housing and the seat separately before the seat is secured to the cylinder housing.

Abstract: An air compressor includes a housing having an air outlet for selectively supplying a pressurized air to an air device, and having a port for coupling to the air device and for drawing the air out of the air device, and having an air inlet for allowing the air to flow into the housing. One or more nozzles each may be selectively and detachably secured to either of the air outlet and the port of the housing for coupling to various kinds of air devices. The air inlet may be selectively blocked for facilitating the drawing of the air into the housing via the port.