Abstract: An electrical tool (1) includes an electric motor (3), a fan wheel (4) that is connected in torque-proof manner to a drive shaft (8) of the electric motor (3) disposed within a housing (2) that includes at least one air inlet aperture (6) and at least one air outlet aperture (7). The at least one air outlet aperture (7) is arranged axially apart from the fan wheel (4) with regard to the axis of rotation (10) of the drive shaft (8). An air guide baffle ring (11) encloses the fan wheel (4) coaxially and has at least one air duct (12) which leads to at least one air outlet aperture (7) located axially at a distance from the fan wheel (4) for cooling the electric tool (1).

Abstract: A cordless system has cordless system components that include a cordless device, such as a cordless power tool, a battery pack and a charger. The battery pack is mated with either the cordless device to provide power to operate the cordless device or to the charger to charge the battery cells in the battery pack. In an aspect, the cordless system has an identification and communication system by which the battery pack identifies and communicates information about the battery pack to the cordless device or to the charger to which the battery pack is mated. In an, the battery pack of the cordless system is capable of multiple modes, such as controlling the cordless device and controlling the charger. In an aspect, the battery pack validates the cordless device or charger to which it is mated.

Abstract: According to an aspect of the present invention, there is provided a power tool including: a motor that generates a rotational force; a power transmission mechanism that is driven by the motor to transmit the rotational force and that is connected to a bit; and a housing that houses the motor and the power transmission mechanism therein, wherein an electric fan for cooling the power transmission mechanism or the motor is provided inside the housing, wherein the power transmission mechanism, the motor and the electric fan are arranged in this order from front, and wherein the electric fan is disposed at a rear side so as to be interposed between the motor and a back wall of the housing.

Abstract: A power tool 1 includes a cylindrical-shaped yoke 31, magnets 32 provided in the interior of the yoke 31, an armature 41 disposed rotatably in the interior of the yoke 31, a cooling fan 7 rotatably secured to the armature 41, a fan guide 8 disposed on the periphery of the cooling fan 7, and a cylindrical-shaped housing 2 for storing the yoke 31 therein. The fan guide 8 is contacted with the axial-direction one end face of the yoke 31, and the fan guide 8 is engaged with the yoke 31 in the rotation direction thereof.

Abstract: A rechargeable electric power tool includes a motor driven by a secondary battery, a switching element for regulating power distribution to the motor, a motor control unit for controlling rotation of the motor through the switching element, a lead wire for supplying a drive current to the motor therethrough and a trigger switch changed over by a user for turning on or off the drive current supplied to the motor through the lead wire. In the rechargeable electric power tool, upon changeover of the trigger switch, a microcomputer determines a magnitude relation between a detected temperature outputted from a first thermistor and a first temperature threshold value. If the detected temperature is determined to be greater than the first temperature threshold value, the microcomputer is set in a limited operation mode in which a revolution number of the motor is limited to a predetermined value or less.

Abstract: In a rechargeable electric power tool, upon changeover of a trigger switch, a microcomputer determines the magnitude relation between the detected temperature outputted from the first thermistor and the first temperature threshold value, the second temperature threshold value and the third temperature threshold value, and the magnitude relation between the first calculated temperature increase rate and the first preset temperature increase rate. If the detected temperature is determined to be greater than the first temperature threshold value or if the first calculated temperature increase rate is determined to be greater than the first preset temperature increase rate after the detected temperature has been determined to be greater than the second temperature threshold value, the microcomputer is set in a limited operation mode in which the revolution number of the motor is limited to a predetermined value or less.

Abstract: An electrical combination including a driver drill capable of producing an average current draw of approximately 20-amps, a circular saw capable of producing an average current draw of approximately 20-amps, and a power tool battery pack operable to supply power to the driver drill and to the circular saw, the battery pack including a plurality of battery cells, the plurality of battery cells each having a lithium-based chemistry.

Abstract: A portable electrical device requiring periodic recharging mates with a corresponding charging device by dropping or placing the portable device on or in the charger without pre-alignment by the user. The charger-to-device interface self aligns the portable electrical device in the charger for charging. Preferably, the charger is a bowl-shaped cradle. The portable device sinks to the bottom of the bowl using the force of gravity and thus aligns the contacts for recharging. Optional magnets may provide additional force to guide alignment.

Abstract: The present invention relates to a power-wrench comprising an electrical converter-fed motor having a permanent-magnetized rotor and a stator provided with winding, the motor winding (1) comprising at least two winding parts, which independently of each other are connected and disconnected by a switch-over device (4). According to the invention, a first winding part (2) may be arranged to control the magnetic field of the motor so that the motor, having the first winding part (2) connected, is adapted for the threading-down phase of the nut driving and operates with low torque and high number of revolutions adapted to said phase, as well as that a second winding part (3) may be arranged to control the magnetic field of the motor so that the motor, having the second winding part (3) connected, is adapted for the final-threading phase of the nut driving and operates with high torque and low number of revolutions adapted to said phase.

Abstract: A power tool cooling system comprises a cooling fan disposed on a motor in a position between the upper field coil and the lower commutator. A transmission housing encapsulates the transmission mechanism. During operation, the fan is driven by the motor and draws air axially through the motor and expels the air radially outwardly through holes in the outer housing of the motor. This causes air to be drawn in through the air vents formed on the top of a tool housing, in the side of the housing and between the housing and a battery pack. The cool air flows outside of the transmission housing, but inside the tool housing such that air does not pass through the transmission mechanism. A plurality of motor openings are also formed in the outer housing of the motor to enable cool air to pass into the motor to cool the motor.

Abstract: In accordance with the invention, a drill comprises a drill housing with a handle portion and a driver portion. An electrical drill motor is located in the driver portion. The drill motor has an output shaft for coupling output rotary power. An electrical switch controls the operation of the drill motor. The electrical switch it is located on the handle portion of the drill housing. A chuck is coupled to the output shaft of the drill motor. A display combines information or state of charge of the battery and drill direction without unduly compromising battery life.

Abstract: A stator of an electrical machine has a cross section, a longitudinal extension, a jacket surface, a plurality of winding holders configured for receiving field windings, the winding holders being distributed inhomogenously around an inner circumference of the cross section, such that a density of the field windings in at least one first region formed around a stator circumference is smaller than in an adjacent second region.

Abstract: A stater of an electrical machine has a cross section, a longitudinal extension, a jacket surface, a plurality of winding holders configured so that at least one of the winding holders for receiving a field winding has a larger winding width than another of the winding holders.

Abstract: In accordance with an aspect of the present disclosure, a power tool has an electric motor having a stator disposed in a field case. The stator has field coils having opposed axial ends that extend axially outwardly from opposed axial ends of a lamination stack of the stator. An armature is disposed in the stator and has a shaft on which a fan is disposed. There are gaps between the opposed axial ends of the respective field coils. The fan baffle includes an air direction member that extends into one of the gaps to direct air flow between the armature and the stator. In an aspect, the fan baffle includes a plurality of such members, one for each gap.

Abstract: A device for impacting a fastener in one embodiment includes a frame, a motor mounted to the frame and including a drive shaft defining a drive shaft axis, a lever arm including a pivot axis parallel with the drive shaft axis, a flywheel rotatably mounted on the lever arm and operably connected to the motor for storing energy received from the motor, a drive mechanism for impacting a fastener, and a solenoid configured to pivot the lever arm between a first position wherein the flywheel is spaced apart from the drive mechanism and a second position wherein the flywheel can contact the drive mechanism.

Abstract: A power tool has a mechanism for ejecting a battery pack which includes a receiving frame which defines a cavity to receive a battery pack. A receiving member is adjacent the cavity. The receiving member meshes with a member on the battery pack to hold the battery pack in the cavity. A biasing member is in the cavity adjacent the receiving member. The biasing member ejects the battery pack from the ejecting mechanism. A member retains the biasing member in the cavity. The member guides a portion of the battery pack meshing with the receiving member into contact with the biasing member such that when the battery pack is locked onto the frame, the biasing member is in a compressed condition and when the battery pack is an unlocked position, the biasing member ejects the battery pack from the frame.

Abstract: An electric motor has a rotor and a stator. The rotor or the stator has arced permanent magnets that have essentially the same inner radius (IR) and outer radius (OR). In an aspect, the stator has a stator housing having a plurality of poles. Each pole includes a plurality of flat magnets affixed to an inner surface of the stator housing. In an aspect, flats on the outside of the stator housing key the stator assembly in a power tool housing. In an aspect, flat magnets are pre-magnetized, pre-assembled with alternating magnetic polarities, inserted into a stator housing, and remagnetized to a final, desired magnetic polarity configuration. In an aspect, pre-magnetized magnets and unmagnetized magnets are pre-assembled with unmagnetized magnets between magnetized magnets, the pre-assembled magnets inserted into a stator housing, and the unmagnetized magnets magnetized to a final, desired magnetic polarity configuration.

Abstract: According to an aspect of the present invention, there is provided a power tool including: a housing; a fan rotatably supported by the housing so as to generate an air flow; a wall portion supported by the housing; and a heat generation portion supported by the wall portion, wherein the wall portion has an exposing hole to expose a part of the heat generation portion so that the exposed part of the heat generation portion is positioned within the air flow.

Abstract: A permanent magnet electric motor has a stator and a rotor The stator has a stator housing with opposed axial ends and features skived in the stator housing to extend radially inwardly from an inner surface of the stator housing proximate to at least one of the axial ends of the stator housing. An overmolding of material is molded around the features. In an aspect, the overmolding of material is a magnetic composite material and is molded to form magnets. In an aspect, magnets are placed on the inner surface of the stator housing and the overmolding of material is a plastic that is over molded around the magnets and the features. In an aspect, the features hold the magnets in place during the molding of the overmolding around the magnets. In an aspect, the magnets have essentially the same inner radius and outer radius and the overmolding of material is thicker at edges of each magnet than at the center of each magnet.

Abstract: A device for locking a power tool and a rechargeable battery pack that is insertable in a guide of the power tool has a locking bar installable on a housing of the power tool and held in locking engagement with the rechargeable battery pack via spring force, a release mechanism that acts on the locking bar for manually releasing the locking bar from the locking engagement, the locking bar and the release mechanism forming a lever that is pivotally supportable in a rocker pivot on the housing, the locking bar being fixedly held via spring force and a recess formed at a top side of the rechargeable battery pack and is releasable by pivoting the lever from the locking engagement via a compression force applied to the release mechanism, which extends upwardly across a front base end of the housing.

Abstract: A portable power working machine includes a drive unit disposed in a motor housing connected to a proximal end of an operating arm. The drive unit rotates a cutting blade at a distal end of the operating arm. The motor housing has an inlet and an outlet for cooling air in front and rear sections, respectively. The drive unit includes an electric motor disposed near the front end of the motor housing, a cooling fan disposed near the rear end of the motor housing and connected to an output shaft of the electric motor, and a heat sink disposed between the cooling fan and the electric motor so as to extend from the electric motor. The cooling air drawn in through the inlet by the cooling fan is guided through a gap between the drive unit and an inner surface of the motor housing and is discharged through the outlet.

Abstract: A drive unit (2) for a hand-held power tool includes a stator (8) located in the drive unit housing (6), an end member (12) provided at each of the opposite ends (10) of the stator (8), a rotor (14) provided with at least one permanent magnet (16), arranged in a receiving space (20) limited by the stator (8) and the end members (12), and the rotatably supported by a drive axle (18) on the end members (12); and a fan (22) rotatably connected with the drive axle (18) for generating a cooling flow (K) from one stator end (10) to another stator end (10) between an inner surface (26) of the drive unit housing (6) and an outer surface (28) of the stator (8) for cooling the stator (8) and the drive unit, with the stator outer surface (28) being provided with a plurality of deflection surfaces (32) extending transverse to the longitudinal extent (L) of the stator (8).

Abstract: An electric motor for use with a power tool includes a motor housing having a first end and an open second end, a first bearing coupled to the first end of the motor housing, a plurality of magnets coupled to the motor housing, and an armature having a first end and a second end. The first end of the armature is rotatably supported by the first bearing. The second end of the armature protrudes from the open second end of the motor housing without being supported by the open second end of the motor housing. The electric motor also includes a second bearing coupled to the second end of the armature. The motor housing is supportable by a first portion of the power tool housing. The second bearing is supportable by a second portion of the power tool housing.

Abstract: The invention relates to a machine tool comprising an electric motor (2) which serves to drive a tool and which has an adjustable, electric brush arrangement (3), and comprising a mode selector switch (6) having various switch positions. Provision is made for an adjusting device (8) to displace the brush arrangement (3) as a function of the switch position of the mode selector switch (6). Furthermore, the invention relates to a corresponding method.

Abstract: To provide a rotary tool driven by a brushless motor with which constant torque tightening work for screws or the like can always be performed properly and efficiently, in which overall downsizing and improved torque control precision enhancement can easily be achieved, and with which it is possible to eliminate occurrences of switch contact-induced sparking and wear and of the damage imparted to the peripheral electronic equipment and electronic circuitry as occurred in drive switches or torque detection mechanisms that use a conventional mechanical switch mechanism, so that the constituting parts are able to have a reduced size and an extended life.

Abstract: An object of the present invention is to effectively cool the generation of heat of a resin molding armature, especially to effectively cool the generation of heat of a coil in an electric motor having a resin molding armature and in an electric tool into which the electric motor is incorporated. In order to effectively cool the generation of heat of a resin molding armature 2a, especially in order to effectively cool the generation of heat of a coil 2e, an open groove 2j is provided for each slot 2g on an outer circumferential face of a molding resin filling layer 9a, which is filled into the slot 2g of a core 2f, in which the coil 2e is embedded. A molding die used for forming a molding resin filling layer 9a is made up of four members which can be split in four sliding directions (in the radial direction of the core).

Abstract: A rechargeable power tool includes a direct current motor, a switching circuit, at least one speed setting unit, a duty ratio setting unit, a drive unit, an operation amount detecting unit, an abnormality determining unit, and a determination threshold setting unit. The abnormality determining unit compares an operation amount detected by the operation amount detecting unit and a determination threshold set based on the operation amount to thereby determine whether or not an operation state of the rechargeable power tool is abnormal. The determination threshold setting unit sets the determination threshold in a continuous or stepwise manner in accordance with a rotation speed set by the speed setting unit.

Abstract: A fastener driving tool arranged to drive fasteners into a workpiece includes at least one electric motor having a central stator and an external rotor arranged to rotate around the stator. The rotor may be in the form of a flywheel. The tool includes an energy transfer member such as a driver arranged to transfer kinetic energy from the rotor to a fastener held in the tool, thereby to drive the fastener from the tool into a workpiece. The electric motor may be a brushless motor. The tool may include two such motors, arranged such that both of their rotors propel the driver simultaneously.

Abstract: A motor controller for controlling at least one electric motor has an operating signal generator for generating an operating control signal for the at least one electric motor and also a sound signal generator for generating a sound control signal. A mixer superimposes the sound control signal on the operating control signal in order to obtain a control signal for the at least one electric motor. It is then possible to dispense with loudspeakers and the like in the appliance which contains an electric motor with such a motor controller in order to output, for example, signal tones which indicate an operating state of the appliance to the user.

Abstract: A kit comprising a plurality of power tools configured to operate at different voltages, a plurality of receivers configured to provide different output charging voltages and means for selectively engaging each receiver with only one or more power tools having an operating voltage equal to or greater than the output charging voltage of the receiver to charge the one or more power tool. The selective engagement means being in the form of a plurality of terminal block. Each terminal block may be secured to a respective one of the power tools. Each terminal block may include a rib and each receiver may define a slot to receivingly engage one of the ribs. The rib of each terminal block may be disposed at a different location than the ribs of the other terminal blocks, and the slot of each receiver may be positioned at a different location than the slots of the other receivers.

Abstract: A device for sensing a direction of rotation of a hand tool having an electric motor, has a rotatably supported brush plate provided in the electric motor and located in different positions depending on a direction of rotation of the electric motor; and at least one sensor which senses the different positions of said brush plate to determine a direction of rotation, wherein said sensor is configured as a contactless sensor.

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: A power tool, having attached thereto a battery device including one or a plurality of cell assemblies, includes a motor which is supplied with a DC current from the battery device, a switching element which controls a drive and a stop of the motor, means which detects a number of cell assemblies, and control means which controls the switching element in such a way as to stop the drive of the motor when the number of cell assemblies is smaller than a prescribed value.

Abstract: An electric mains-connection device for an electric hand-held power tool equipped with an electric motor (M), in particular for an angle grinder, has mains-connection terminals for a mains-connection cable, and with an anti-interference capacitor; it is designed as a mains-connection module that can be actuated externally, includes mains terminals, houses the anti-interference capacitor, and out of which an electric cable extends, which serves to connect motor electronics and a motor switch in an interface-free manner. An electric device for an electric hand-held power tool equipped with an electric motor, in particular for an angle grinder, includes the electric mains-connection device.

Abstract: An electrical hand tool device (2) comprises a ventilated housing body (4), which has inlet and outlet openings (6, 8) for cooling air flow and accommodates the electromotive components (12) of the device, in particular, a motor (14) that is excited by a permanent magnet and is powered by a battery, and a magnet (22, 24) that is provided in the area of the cooling air flow for absorbing magnetic or magnetizable dust. In order to protect the electric motor, the device is designed in such a fashion that at least two magnets (22, 24) are provided in the axial direction (26) between the inlet openings (6, 8) and the electromotive components (12) of the device, and a means (30) is provided, which electrically cooperates with the at least two magnets (22, 24) to determine whether a substantial amount of magnetizable dust has collected on the magnets (22, 24), in which case, a control measure can be performed.

Abstract: An improved power tool system includes a power tool and an external power supply connected via a cable to provide utility and safety in a hazardous operation such as loading ammunition into a weapon in an environment of flammable materials and extreme environmental exposure. The power tool includes a sparkless motor, a sparkless controller and sparkless switches, in a sealed enclosure with improved heat transfer means. The power tool has improved torque controlling means to mitigate reaction torque to the operator and equipment when starting or stopping highly inertial loads. A sealed enclosure is provided to prevent liquids from entering the motor and controller cavity and includes a thermally conductive path to conduct heat from the motor and controller through the enclosure to cooling fins and a coolant path formed between the fins and an entrapment wall.

Abstract: A handheld power tool has a housing, a tool receptacle, a motor having a motor shaft, an intermediate shaft, an element for transmitting a rotation of the motor shaft to a rotary motion of the intermediate shaft, a drive mechanism for a tool insertable into the tool receptacle, the drive mechanism being provided with an element for converting the rotary motion of the intermediate shaft into a rotary motion of the tool receptacle and an element for converting the rotary motion into the intermediate shaft into a hammering motion of the tool receptacle, wherein the motor shaft is coaxial with the intermediate shaft, and there is an element for coupling the motor shaft to the intermediate shaft.

Abstract: A hammer drill comprising a body (2) containing an electric motor (4) for driving an output (6) of the drill is disclosed. A vibration transducer (12) senses vibrations generated by the motor and produces a vibration signal dependent upon the sensed vibrations. An electronic module (10) includes a controller (10a) for controlling the rotational speed of the motor, and a signal processor (10b) for receiving the vibration signal from the vibration transducer, determining the rotational speed of the motor based on the vibration signal, and providing an output signal to the controller to cause the controller to control the rotational speed of the motor.

Abstract: According to an aspect of the invention, there is provided a power tool including: a commutator motor including a rotor and a stator having a substantially cylindrical stator core; a fan provided to face one axial end of the stator core so as to be rotatable coaxially with the rotor; and a stator coil bundle fixed to an inner peripheral surface of the stator core, the stator coil bundle having a coil end portion that protrudes more than the stator core in a rotational axis direction of the rotor, wherein a minimum internal diameter of the coil end portion is smaller than a maximum external diameter of the fan, and wherein the coil end portion has a fan facing portion that faces the fan along a direction perpendicular to the rotational axis direction.

Abstract: A power tool having a cooling system, comprises: a motor housing 11 having a main chamber 14 accommodating a tool motor 12; a handle 15 for holding the power tool and having a cooling passage 16 for the transfer of cooling fluid, at least one inlet 18 leading to the cooling passage and at least one outlet 13 leading away from the cooling passage 18, and a power tool component 21 which generates heat disposed in thermal contact with the cooling passage 16 between the inlet 18 and the outlet 13.

Abstract: A portable motorized device (1) for gardening tools having a crankcase (2), a motor (3) housed in the crankcase (2), a drive shaft (4) associated with the motor (4) and suitable for actuating a tool, control device (7) of the motor (3), where said crankcase (2) comprises two hollow substantially symmetrical portions (2a, 2b) divided vertically along a plane parallel to the rotation axis of the drive shaft (4), a grip (5; 55) with which control device (7) of the motor are associated.

Abstract: An electric impact tightening tool in which the rotation of an output section of an electric motor is transmitted to an impact generation section (P) and impact force generated in the impact generation section (P) causes a main shaft (107) to produce strong torque, where the electric motor is an outer rotor electric motor (M). The outer rotor electric motor (M) has low-speed, high-torque characteristics. In the tool, the impact generation section (P) and a rotor flange (61) at the forward end of the motor (M) are adapted to rotate integrally. The electric impact tightening tool is small sized and lightweight, produces low reaction force, and has durability.

Abstract: A power tool includes a tool housing and a motor. The motor includes a commutator and a brush assembly around the commutator. The brush assembly has two pieces. The power tool is assembled by inserting the first piece of the brush assembly in a first portion of the housing of the power tool, inserting a frameless motor in the first portion of the power tool housing, mating the second piece of the brush assembly to the first piece, and mating a second portion of the power tool housing to the first portion of the power tool housing.

Abstract: An electronic handheld device with remote cable release mechanism, a handle portion and method for performing the same. The device includes a housing defining an internal cavity and has an elastically deformable flexible portion. An electrical connector block is disposed in the cavity and includes a female receptacle configured for receiving a male electrical cable connector having a movable locking clip configured to releasably engage the connector block. An actuating protrusion is preferably disposed on the flexible portion of the housing for releasing the cable connector. The protrusion is movable towards the connector block in response to the application of an inward pressing force on the flexible portion. The protrusion operates to depress the locking clip on the cable connector, thereby releasing the cable connector. In another embodiment, a resealable dimple may be provided in the flexible portion which can be punctured via a probe to access the locking clip.

Abstract: An apparatus converts rotary motion of a motor drive shaft into oscillatory motion of a work piece, for example, in a power tool. The apparatus comprises a planetary gear assembly connected to the motor for rotating an output gear. The output gear meshes with a drive gear including a drive pin. The drive pin fits in a yoke slot for reciprocation of the yoke upon rotation of the drive gear. The yoke is operatively connected to the work piece. An air flow system cools the power tool housing. The housing has an inlet aperture in the handle portion and an outlet aperture for placing the interior of the housing in communication with the atmosphere. A wall integral with the handle portion engages the body of the motor housing between a first end and openings in the body.

Abstract: A method of assembling a power tool, a power tool, a method of assembling an electrical device, and an electrical device includes a switched reluctance motor. The electrical device is preferably a hand-held power tool, however, any type of electrical device that includes a switched reluctance motor may benefit from any number of aspects of the invention. In one independent aspect, the invention provides a construction that reduces tolerance stack-up. In another independent aspect, the invention provides a self-contained electronics package that plugs into a switched reluctance motor to provide control operation of the switched reluctance motor. In another independent aspect, the invention provides enhanced cooling that increases the efficiency of the electrical device using a switched reluctance motor. In another independent aspect, the invention provides an encapsulated magnet that allows for contaminant free motor control over the life of the SR motor.

Abstract: A handheld electric mixer has a variable speed motor and a two-speed gearbox for transmitting driving torque of the motor to a pair of work pieces that mix, blend, beat or otherwise act upon a food item or recipe constituents. The gear box has a first gear ratio for providing a first range of output speeds and a second gear ratio for providing a second range of output speeds. The first ratio transmits at least twice as much torque to the rotational work pieces as does the second ratio. There is an electronic speed controller for controlling rotational speed the motor and a separate ratio selector for selecting between the first and second ratios of the gearbox.

Abstract: A battery device is constituting by connecting such cell assemblies in parallel as each comprises: a first cell group having a plurality of cells connected in series; a housing container for housing said first cell group; current detecting means housed in said container for detecting a current to flow through the first cell group; a switching element connected with said first cell group for turning ON/OFF the current to flow through said first cell group; and means for controlling the ON/OFF of said switching element in response to the output signal of said current detecting means.

Abstract: A power hand tool includes a housing; an electric motor mounted in the housing for provide a rotary motion; a transmission gear set is mounted in the housing and connected with the electric motor; a torsion control device having a first rotary knob, which can adjust the maximum torsion output of the transmission gear set while being turned, and a plurality of first dents formed on an internal periphery thereof; an impact device having a second rotary knob, which can switch on or off an impact motion generated on the transmission gear set while being rotated, and a plurality of second dents formed on an internal periphery thereof; and a locating device having a holder fixed to the torsion control device and a locating member mounted to the holder, the locating member having two resilient portions, each of which has a convexity engaged with the associated first dents or second dents.

Abstract: A rotor (2) for a forced-air-cooled electric motor, in particular a universal motor, especially for use with electrical power tools, has a laminated armature (6) incorporating longitudinal slots (8) and with wire windings of a coil (10) protruding from the longitudinal slots (8) on the front face where the windings form coil connecting heads (20, 22). Some or all of the longitudinal slots (8) in the laminated armature (6) contain a rod (28) aligned in the longitudinal direction and protruding axially from one or both front faces (24, 26) of the laminated armature (6), whereby the protruding rod ends thus surround the coil connecting heads (20, 22) on the respective front face to protect the coil connecting heads from abrasive wear.