The invention relates to a door closer having high usability and capable of saving installation cost. The door closer according to an example embodiment of the inventive concept includes a first closer part combined with a doorframe and a door to provide a rotational force in a direction in which the door is closed, and a second closer part to reduce a rotational speed of the door by a damping force of a viscous fluid contained thereinside when the door is closed by the first closer part.

A reel damper includes a base, a cap, a ring gear, a torsion spring, and a sun gear. The cap is secured to the base, and the ring gear is rotatably engaged with the base. The torsion spring is engaged with the base and the ring gear. The sun gear is disposed in and meshed with the ring gear.

A reel damper includes a base, a cap, a ring gear, a torsion spring, and a sun gear. The cap is secured to the base, and the ring gear is rotatably engaged with the base. The torsion spring is engaged with the base and the ring gear. The sun gear is disposed in and meshed with the ring gear.

A cover plate device comprises a cover plate, a support plate and the damping assembly, wherein the cover plate is located at the upper part of the support plate, the damping assembly is provided on one side edge of the cover plate, and the assisting damper and a rotating damper are respectively connected with a support shaft on the support plate, so that the cover plate is rotatably connected with the support plate. The assisting damper comprises a shell I, a pin roll, a driving shaft, a driven shaft and a spring assembly, wherein a damper working chamber is arranged in the shell I; the driving shaft, the driven shaft and the spring assembly are all located in the damper working chamber; and when the driving shaft rotates, the driven shaft is driven to translate along the length direction of the damper working chamber.

A cover plate device comprises a cover plate, a support plate and the damping assembly, wherein the cover plate is located at the upper part of the support plate, the damping assembly is provided on one side edge of the cover plate, and the assisting damper and a rotating damper are respectively connected with a support shaft on the support plate, so that the cover plate is rotatably connected with the support plate. The assisting damper comprises a shell I, a pin roll, a driving shaft, a driven shaft and a spring assembly, wherein a damper working chamber is arranged in the shell I; the driving shaft, the driven shaft and the spring assembly are all located in the damper working chamber; and when the driving shaft rotates, the driven shaft is driven to translate along the length direction of the damper working chamber.

A damper is provided which can more reliably prevent malfunction and breakdown and which enables efficiently performing repair and inspection operations. This damper, provided with a casing linked to a first object and a rotating part linked to a second object rotatably attached to the first object, damps rotation in either the direction closing or the direction opening the second object, and is provided with a sensor which detects prescribed change in the external environment in the damper or around the damper, and a control unit which externally communicates, over a communication network, information relating to the change in the external environment detected by the sensor, wherein the sensor is configured from at least one of: a rotation sensor for detecting the number of revolutions of the rotating part: a sound sensor for detecting sound during rotations of the rotating part; a temperature sensor for detecting temperature; and a torque sensor for detecting torque on the basis of friction during rotation of the rotating part.

A damper is provided which can more reliably prevent malfunction and breakdown and which enables efficiently performing repair and inspection operations. This damper, provided with a casing linked to a first object and a rotating part linked to a second object rotatably attached to the first object, damps rotation in either the direction closing or the direction opening the second object, and is provided with a sensor which detects prescribed change in the external environment in the damper or around the damper, and a control unit which externally communicates, over a communication network, information relating to the change in the external environment detected by the sensor, wherein the sensor is configured from at least one of: a rotation sensor for detecting the number of revolutions of the rotating part: a sound sensor for detecting sound during rotations of the rotating part; a temperature sensor for detecting temperature; and a torque sensor for detecting torque on the basis of friction during rotation of the rotating part.

A linear damper includes a rack, a carriage, a gear assembly, and a spring. The rack includes a connector. The carriage is slidably engaged with the rack. The gear assembly is between the carriage and the rack. The spring is secured to the rack to selectively urge the carriage away from the connector.

A damper has a shell with a cavity. A rotating shaft is rotatably inserted into the cavity of the shell, the portion of the rotating shaft located in the cavity is provided with external thread; a guiding sleeve with internal thread can move along axially reciprocatingly to attach to the shell cavity, and the internal thread and the male thread of the rotating shaft are screwed together; A guiding structure is provided in the shell cavity. The guiding sleeve is engaged or disengaged with the guiding structure by axial movement, and when the two are disengaged, the guiding sleeve can rotate with the rotating shaft. The guiding sleeve is provided with a one-way valve passage. The one-way valve passage opens when the guiding sleeve is axially disengaged with the guiding structure. When the guiding sleeve moves axially in the reverse direction, the one-way valve passage is closed.

A damper has a shell with a cavity. A rotating shaft is rotatably inserted into the cavity of the shell, the portion of the rotating shaft located in the cavity is provided with external thread; a guiding sleeve with internal thread can move along axially reciprocatingly to attach to the shell cavity, and the internal thread and the male thread of the rotating shaft are screwed together; A guiding structure is provided in the shell cavity. The guiding sleeve is engaged or disengaged with the guiding structure by axial movement, and when the two are disengaged, the guiding sleeve can rotate with the rotating shaft. The guiding sleeve is provided with a one-way valve passage. The one-way valve passage opens when the guiding sleeve is axially disengaged with the guiding structure. When the guiding sleeve moves axially in the reverse direction, the one-way valve passage is closed.