Abstract: The power tool has a power transmitting mechanism. When a tool bit is not pressed against a workpiece, the power transmitting mechanism is held in a power transmission interrupted state, and when the tool bit is pressed against the workpiece, the power transmitting mechanism is held in a power transmission state in which the tool bit moves together with the driven-side member in an axial direction of the tool bit so that the driving-side member receives the torque from the driven-side member and the tool bit is driven. Tapered portions are provided between the driving-side member and the driven-side member and inclined with respect to the axial direction of the tool bit. When the driven-side member moves in the axial direction of the tool bit, frictional force is caused on the tapered portions and the torque of the driving-side member is transmitted to the driven-side member by the frictional force.

Abstract: A power tool that includes a driving motor and a power transmitting mechanism. The power transmitting mechanism includes a first clutch cam part, a second clutch cam part, clutch teeth, a clutch detecting mechanism and a controller that can control the driving motor in a first control mode in which the driving motor is controlled to rotate at a first rotation speed until before the first and second clutch cam parts are engaged with each other at the clutch teeth and in a second control mode in which the driving motor is controlled to rotate at a second rotation speed higher than the first rotation speed after the first and second clutch cam parts are engaged with each other at the clutch teeth.

Abstract: The present invention provides an electrode that can be used for a sodium secondary battery having a larger discharge capacity when charging and discharging are performed repeatedly than that of the prior art. This sodium secondary battery electrode contains tin (Sn) powder as an electrode active material. The electrode, particularly, further contains one or more electrode-forming agents selected from the group consisting of poly(vinylidene fluoride) (PVDF), poly(acrylic acid) (PAA), poly(sodium acrylate) (PAANa), and carboxymethylcellulose (CMC), thereby making it possible to provide a sodium secondary battery having even greater electrode performance.

Abstract: An additive for a sodium ion secondary battery of the present invention includes a compound of at least one of a saturated cyclic carbonate having a fluoro group and a chain carbonate having a fluoro group. A sodium ion secondary battery (1) of the present invention includes: a non-aqueous electrolytic solution including the additive for a sodium ion secondary battery and a non-aqueous solvent containing a saturated cyclic carbonate or a non-aqueous solvent containing a saturated cyclic carbonate and a chain carbonate; a positive electrode (11); and a negative electrode (12) that includes a coating formed in a surface of the negative electrode, the coating containing a composite material having carbon, oxygen, fluorine and sodium in the surface and includes a negative-electrode active material containing a hard carbon.

Abstract: A power tool that includes a driving motor and a power transmitting mechanism. The power transmitting mechanism includes a first clutch cam part, a second clutch cam part, clutch teeth, a clutch detecting mechanism and a controller that can control the driving motor in a first control mode in which the driving motor is controlled to rotate at a first rotation speed until before the first and second clutch cam parts are engaged with each other at the clutch teeth and in a second control mode in which the driving motor is controlled to rotate at a second rotation speed higher than the first rotation speed after the first and second clutch cam parts are engaged with each other at the clutch teeth.

Abstract: The power tool has a power transmitting mechanism. When a tool bit is not pressed against a workpiece, the power transmitting mechanism is held in a power transmission interrupted state, and when the tool bit is pressed against the workpiece, the power transmitting mechanism is held in a power transmission state in which the tool bit moves together with the driven-side member in an axial direction of the tool bit so that the driving-side member receives the torque from the driven-side member and the tool bit is driven. Tapered portions are provided between the driving-side member and the driven-side member and inclined with respect to the axial direction of the tool bit. When the driven-side member moves in the axial direction of the tool bit, frictional force is caused on the tapered portions and the torque of the driving-side member is transmitted to the driven-side member by the frictional force.

Abstract: It is an object of the invention to provide an effective technique for preventing loss of a screw fastening depth regulating member removed from a machine body in a screw fastening machine. A representative screw fastening machine includes a machine body, a motor, an input shaft, an output shaft, a first clutch element, a second clutch element, a biasing member for first and second clutch elements, a screw fastening depth regulating member. The machine body has a holding part formed in an area other than the tip end region of the machine body to removably hold the screw fastening depth regulating member. The holding part is provided such that the screw fastening depth regulating member can be attached to and removed from the holding part by utilizing elastic deformation of the holding part.

Abstract: It is an object of the invention to provide an effective technique for preventing loss of a screw fastening depth regulating member removed from a machine body in a screw fastening machine. A representative screw fastening machine includes a machine body, a motor, an input shaft, an output shaft, a first clutch element, a second clutch element, a biasing member for first and second clutch elements, a screw fastening depth regulating member. The machine body has a holding part formed in an area other than the tip end region of the machine body to removably hold the screw fastening depth regulating member. The holding part is provided such that the screw fastening depth regulating member can be attached to and removed from the holding part by utilizing elastic deformation of the holding part.