Abstract: When a battery pack having an output voltage of 14.4 V that is connectable to an electric tool in a sliding manner is used as a power supply source for the electric tool that is connectable to a battery pack in an insertion manner and has a rated voltage of 12 V, the electric tool and the battery pack are connected to each other with an adaptor interposed therebetween. The adaptor has an FET that is switched at a predetermined duty of a predetermined frequency. The battery pack and the electric tool are connected or disconnected to or from each other by the switching operation, thereby dropping the output voltage of the battery pack. When the detected voltage is out of a predetermined value range, it is judged that the overcurrent or overdischarge has occurred. Then, the FET is turned off to stop the electric tool.

Abstract: An adapter includes an insertion part that is inserted into a body of a power tool and has terminals for electrically connecting with the power tool; a pair of rails for guiding insertion of a battery pack in a direction substantially orthogonal to the insertion direction of the insertion part; an operating part constituting tool-latching device for attaching to and detaching from the body of the power tool; and a receiving part constituting battery-latching device for attaching to and detaching from the battery pack. The operating part of the tool-latching device and the receiving-side of the battery-latching device are disposed in different positions when viewing the adapter in the insertion direction of the insertion part.

Abstract: When a battery pack having an output voltage of 14.4 V that is connectable to an electric tool in a sliding manner is used as a power supply source for the electric tool that is connectable to a battery pack in an insertion manner and has a rated voltage of 12 V, the electric tool and the battery pack are connected to each other with an adaptor interposed therebetween. The adaptor has an FET that is switched at a predetermined duty of a predetermined frequency. The battery pack and the electric tool are connected or disconnected to or from each other by the switching operation, thereby dropping the output voltage of the battery pack. When the detected voltage is out of a predetermined value range, it is judged that the overcurrent or overdischarge has occurred. Then, the FET is turned off to stop the electric tool.

Abstract: When a battery pack having an output voltage of 14.4 V that is connectable to an electric tool in a sliding manner is used as a power supply source for the electric tool that is connectable to a battery pack in an insertion manner and has a rated voltage of 12 V, the electric tool and the battery pack are connected to each other with an adaptor interposed therebetween. The adaptor has an FET that is switched at a predetermined duty of a predetermined frequency. The battery pack and the electric tool are connected or disconnected to or from each other by the switching operation, thereby dropping the output voltage of the battery pack. The voltage from the battery pack is detected. When the detected voltage is out of a predetermined value range, it is judged that the overcurrent or overdischarge has occurred. Then, the FET is turned off to stop the electric tool.

Abstract: An adapter includes an insertion part that is inserted into a body of a power tool and has terminals for electrically connecting with the power tool; a pair of rails for guiding insertion of a battery pack in a direction substantially orthogonal to the insertion direction of the insertion part; an operating part constituting tool-latching device for attaching to and detaching from the body of the power tool; and a receiving part constituting battery-latching device for attaching to and detaching from the battery pack. The operating part of the tool-latching device and the receiving-side of the battery-latching device are disposed in different positions when viewing the adapter in the insertion direction of the insertion part.

Abstract: When a battery pack having an output voltage of 14.4 V that is connectable to an electric tool in a sliding manner is used as a power supply source for the electric tool that is connectable to a battery pack in an insertion manner and has a rated voltage of 12 V, the electric tool and the battery pack are connected to each other with an adaptor interposed therebetween. The adaptor has an FET that is switched at a predetermined duty of a predetermined frequency. The battery pack and the electric tool are connected or disconnected to or from each other by the switching operation, thereby dropping the output voltage of the battery pack. The voltage from the battery pack is detected. When the detected voltage is out of a predetermined value range, it is judged that the overcurrent or overdischarge has occurred. Then, the FET is turned off to stop the electric tool.

Abstract: A longer life screwdriver is disclosed, and the screwdriver includes a ball retained in a through-hole in a manner movable in a radial direction of a driving shaft member, the through-hole being defined in a driving shaft member, the ball being possible to project beyond the driving shaft member along an outer circumference of the driving shaft member, the ball further being possible to abut an end of a clutch spring, and elements for allowing the ball to protrude beyond the driving shaft member along the outer circumference of the driving shaft member in response to axial movement of the output shaft member against a pressing member, the improvement comprising: disengagement elements for releasing engagement between the clutch spring and the ball during the reverse rotation of a motor.

Abstract: A longer life screwdriver is disclosed, and the screwdriver includes a ball retained in a through-hole in a manner movable in a radial direction of a driving shaft member, the through-hole being defined in a driving shaft member, the ball being possible to project beyond the driving shaft member along an outer circumference of the driving shaft member, the ball further being possible to abut an end of a clutch spring, and means for allowing the ball to protrude beyond the driving shaft member along the outer circumference of the driving shaft member in response to axial movement of the output shaft member against a pressing means, the improvement comprising: disengagement means for releasing engagement between the clutch spring and the ball during the reverse rotation of a motor.

Abstract: Re-powering an electrical equipment after recovery of service interruption is prevented if the power switch of the electrical equipment stays in ON position. During a transit period of time just after recovery of service interruption, the detection voltage from a post-voltage detection circuit is set to exceed the detection voltage from a pre-voltage detection circuit. In this condition, a photo triac connected in series to the power switch is rendered non-conductive so that the electrical equipment will not be energized.

Abstract: An automatic drilling machine has an electric drilling unit on which a cylindrical cutter is rotatably mounted. The drilling machine includes a drill motor for rotating the cutter and a feed motor for linearly moving the cutter for the purpose of drilling into materials such as concrete. The current flowing through the drill motor before a drilling load is imposed thereon is detected for a microprocessor to determine the type of the cutter being used. The drill motor is driven at a rotation speed suitable for the cutter being used and the feed motor is driven at a speed such that the rotation speed of the drill motor thus set is maintained unchanged. Particularly, the drill motor is driven at a reduced rotation speed from the start of drilling until a predetermined drilling depth is reached to reduce chatter vibration which may otherwise be generated if the drill motor is driven at a regular constant speed from the beginning of drilling until the end.

Abstract: A quick-return motion mechanism for use in an automatic magnetic drilling machine including a feed motor for generating power transferred through a worm wheel and a high-ratio reduction gear to a handle shaft to drive an electric drill. A one-way clutch is provided inside the worm wheel so that the handle shaft races on feed and is locked on return. The high-ration reduction gear is composed of elements which are arranged to cause the input and output sides of the high-ratio reduction gear to rotate in the same direction. The quick-return motion mechanism consists of an arrangement for restraining the input side element of the high-ratio reduction gear on feed and for releasing it on return to race the high-ratio reduction gear.

Abstract: A drive motor connected to a drill bit serves to actuate the drill bit. An electric current is allowed to flow through the drive motor to activate the drive motor. A mechanism serves to feed the drill bit with respect to a workpiece. The current flowing through the drive motor is sensed. A device stores a value of the current which is sensed when the drill bit is out of engagement with the workpiece. A determination is made as to whether or not a drilling process is completed in accordance with a value of the present sensed current and the stored value of the sensed current.