Abstract: Disclosed are a clutch device, a drill chuck, a power tool, and a bidirectional rotation method of the drill chuck. The clutch device comprises a return elastic member, a transmission assembly and a rotating portion, wherein the transmission assembly comprises at least two oppositely arranged engagement portions; the engagement between the two engagement portions enables a front body and a rear body to rotate synchronously; the rotation of the rotating portion in a first direction enables the return elastic member to be compressed, such that the two engagement portions are disconnected; and the rotation of the rotating portion in a second direction enables the compressed return elastic member to return to an initial position such that the two engagement portions are engaged. The drill chuck comprises a front body, a rear body, clamping jaws and the clutch device; and the power tool comprises a driving shaft and the drill chuck.

Abstract: A gear self-tightening drill chuck, comprising a rear pressing cover or a retaining ring, a rear body, a main body, a front sleeve, clamping jaws, and driven bevel gears; the rear body is arranged inside the main body; one end of the rear body is provided with a driving bevel gear, the large end thereof being arranged next to the rear body; the driving bevel gear is arranged inside the main body, and is engaged with the driven bevel gears; a plurality of driven bevel gears are arranged uniformly with the axis of the driving bevel gear as the centre line; the driven bevel gears have an inner screw thread; one end of the clamping jaw has an outer screw thread for use together with the inner screw thread; the main body is provided with clamping jaw holes and bevel gear holes.

Abstract: A gear self-tightening drill chuck, comprising a rear pressing cover or a retaining ring, a rear body, a main body, a front sleeve, clamping jaws, and driven bevel gears; the rear body is arranged inside the main body; one end of the rear body is provided with a driving bevel gear, the large end thereof being arranged next to the rear body; the driving bevel gear is arranged inside the main body, and is engaged with the driven bevel gears; a plurality of driven bevel gears are arranged uniformly with the axis of the driving bevel gear as the centre line; the driven bevel gears have an inner screw thread; one end of the clamping jaw has an outer screw thread for use together with the inner screw thread; the main body is provided with clamping jaw holes and bevel gear holes.

Abstract: The present invention provides a new drill chuck that resolves the problem that the excessive clamping force of the existing drill chuck makes it inconvenient to open the drill chuck and easily damages the cutters. The new drill chuck comprises a front-body, an after-body, and clamping jaws, wherein a thread is provided on the clamping jaw, the after-body is provided with master gears, slave gears are provided between the clamping jaws and the after-body, the master gear fits with the slave gear, a thread is provided inside the slave gear, and the thread of the slave gear fits with the thread of the clamping jaw.

Abstract: The present invention provides a new drill chuck that resolves the problem that the excessive clamping force of the existing drill chuck makes it inconvenient to open the drill chuck and easily damages the cutters. The new drill chuck comprises a front-body, an after-body, and clamping jaws, wherein a thread is provided on the clamping jaw, the after-body is provided with master gears, slave gears are provided between the clamping jaws and the after-body, the master gear fits with the slave gear, a thread is provided inside the slave gear, and the thread of the slave gear fits with the thread of the clamping jaw.

Abstract: A device and method of determining a travel direction of a mobile device carried by a user are disclosed. The method includes determining a line along which the mobile device is traveling, where the determining may be based on sensed acceleration of the mobile device. A walking style of the user traveling with the mobile device may be determined. The sensed acceleration may be resolved into at least two mutually perpendicular components. A first component may be substantially parallel with gravity, and a second component may be orthogonal to the first component. The travel direction of the mobile device along the travel line may be determined based on a user's walking style and the resolved sensed acceleration. The determining of the line may include applying a linear least square fitting method to a plurality of acceleration readings obtained from at least one inertial navigation sensor.