Abstract: It is an object of the invention to provide an improved impact tool in which a biasing member is not affected by dust. An impact tool according to the invention has a driving mechanism 120 for driving a tool bit 119, housing parts 105, 106 that form a housing space 105a in which at least part of the driving mechanism 120 is disposed, and a switching member 160 for switching a drive mode of the impact tool. The switching member 160 has an operating member 161 that is operated by a user for mode switching, and a biasing member 175 that is disposed between the operating member 161 and the housing part 106 and biases the operating member 161 so as to hold the operating member 161 in a selected position. The biasing member 175 is disposed in the housing space 105a.

Abstract: A hammer drill serving as an impact tool is provided with a crank housing that accommodates a crankshaft, and a cylinder accommodated in the crank housing. Receiving portions that receive the cylinder which is pressed rearward are provided at multiple locations of the crank housing in the front-rear direction. At least one of the receiving portions is disposed to receive the rear-end portion of the cylinder. A portion of the cylinder, which is received by another one of the receiving portions is a circlip (circumferential member) made of a metal.

Abstract: In a dust collection device attached to a hammer drill, a filter is provided in a dust box at a position at which the filter covers an outlet provided on a rear face of a lid body, in a state such that a filter surface projects into the dust box from the rear face of the lid body. A space is formed between an inner face of a box main body and a side face of the filter that is adjacent to the filter surface. Air outlets are provided to guide air, which flows in through an inlet, toward the space.

Abstract: In the receiving terminal of a PCM (Pulse Code Modulation)-TDMA (Time Division Multiple Access) system, a data is demodulated from a received burst signal, said data is written in a buffer register by using a burst clock which is regenerated from the received burst signal. The content of said buffer register is read by using a local clock which is generated in the receiving office and, after the data is read out, said data is controlled by said local clock.

Abstract: A transmit phase control system of synchronization burst is disclosed for use in a SDMA/TDMA satellite communication system in which a phase error between a synchronization burst transmitted from an earth station and a synchronization window, assigned as a time slot on a satellite for returning the synchronization burst, is measured and the transmit phase of the synchronization burst is controlled based on the measured value. Phase error measurement is achieved a plurality of times in connection with the received synchronization burst of each station, and a decided phase error is derived based on the measured value obtained by the plurality of measurements. The transmit phase of the synchronization burst is then controlled in accordance with the decided phase error.