Abstract: A combustion type power tool capable of restraining reduction in output power due to lowering of combustion efficiency. A specific space within a combustion-chamber frame is enlarged. The specific space contains a specific region where high turbulence occurs in a combustion chamber at which a fuel is ignited. The enlargement is made by providing an enlarged distance between a rotation shaft of the fan and an inner wall of the combustion-chamber frame. When the turbulent combustion occurring at the specific region is expanded in the combustion chamber, flame propagation contour of the turbulent combustion reaches the wall of the combustion-chamber frame and ribs at a delayed timing. Therefore, after the turbulent combustion is sufficiently promoted, the flame reaches the combustion-chamber frame and the ribs. In other words, the flame does not reach the combustion-chamber frame and the ribs at the initial stage of turbulent combustion.

Abstract: Disclosed is an electric power tool having a gear mechanism, which reduces a noise by absorbing collision of gears and is resistible to a high torque. A power transmission key 7 composed of high-strength plastic is provided between an output shaft 3 and a gear 4, and a plane or a V-groove is formed on each of the output shaft 3 and the gear 4 contacting the power transmission key 7.

Abstract: Disclosed is an electric power tool having a gear mechanism, which reduces a noise by absorbing collision of gears and is resistible to a high torque. A power transmission key 7 composed of high-strength plastic is provided between an output shaft 3 and a gear 4, and a plane or a V-groove is formed on each of the output shaft 3 and the gear 4 contacting the power transmission key 7.

Abstract: Disclosed is an electric power tool having a gear mechanism, which reduces a noise by absorbing collision of gears and is resistible to a high torque. A power transmission key 7 composed of high-strength plastic is provided between an output shaft 3 and a gear 4, and a plane or a V-groove is formed on each of the output shaft 3 and the gear 4 contacting the power transmission key 7.

Abstract: Disclosed is an electric power tool having a gear mechanism, which reduces a noise by absorbing collision of gears and is resistible to a high torque. A power transmission key 7 composed of high-strength plastic is provided between an output shaft 3 and a gear 4, and a plane or a V-groove is formed on each of the output shaft 3 and the gear 4 contacting the power transmission key 7.

Abstract: A dot line printer provided with an ordinary dot density printing mode, a low dot density or draft printing mode and a high dot density printing mode. A hammer bank provided with a plurality of printing hammers is reciprocally movable in a shuttling direction for dot impressions when the hammer bank is moved through a printing region, and the moving direction of the hammer bank is reversed at a reversing region where a printing sheet is fed in a line to line direction. A shuttle cam is provided which is drivingly connected to the hammer bank. The shuttle cam has a cam profile capable of providing a cam lift characteristic approximately intermediate between a cam lift characteristics of the ordinary printing mode and that of the low dot density printing mode. A shuttling velocity of the hammer bank is changed in accordance with the selected printing mode and position of the hammer bank.

Abstract: A dot line printer with a paper feed time controlling capability includes a hammer bank accommodating a plurality of print hammers, a shuttle mechanism for shuttling the hammer bank back and forth along a print line, and a sheet feeding mechanism for feeding a sheet of paper in a direction perpendicular to the direction in which the hammer bank shuttles. When a first predetermined amount of a line space feeding is to be carried out after completion of one line printing, a hammer bank reversing time is prolonged. When more than the first predetermined amount of the line space feeding but less than a second predetermined amount of line space feeding is to be carried out, it is carried out during an extended period of time including both the hammer bank reversing time and the subsequent hammer bank scanning time without prolonging the hammer bank reversing time.