Abstract: A hydraulic door closer capable of reducing oil-pressure therein at high temperature, comprises a housing with an oil chamber, an oil storage cavity, and a piston in the housing of the hydraulic door closer. The oil storage cavity is in communication with the oil chamber; when the oil temperature increases, hydraulic oil in the oil chamber and oil storage cavity generates an increased oil pressure move the piston, whereby volume of the oil storage cavity is enlarged, such that oil from the chamber will flow into the cavity, to reduce the oil pressure of the chamber and cavity. When the oil temperature decreases, the oil pressure in the chamber and cavity is reduced, whereby the storage piston restores its original position, whereby volume of the cavity will be reduced, and the oil in the cavity flows back into the chamber. The pressure in the oil chamber is reduced when the hydraulic oil expands due to increased temperature to prevent failure of the seal and to avoid hydraulic oil leakage.

Abstract: A door operator includes a housing and at least one linearly guided piston in the housing. A roller carrier is disposed in the piston and includes a rotatably movable supported pressure roller. The piston is formed as a deep drawn structural component and includes a bottom and a circumferential walling. The support and the axial guiding of the roller carrier with a pressure roller within the piston can be realized in a simple and cost effective manner. Furthermore, an aperture is provided in the bottom of the piston, through which the pressure roller protrudes to the outside beyond the bottom of the piston.

Abstract: A hydraulic hinge for a glass door has a fixing plate, a rotating seat, a pivot and a buffer module. The rotating seat is combined with the fixing plate and has a first oil passage and a second oil passage. The pivot is combined with the fixing plate and the rotating seat. The buffer module is mounted in the rotating seat and has a valve having a circular groove selectively communicating with the second oil passage. A glass door can be pivoted relative to the rotating seat. The valve is structurally simple, thereby simplifying the manufacturing process. With the valve and the second oil passage, the velocity of closing the glass door gradually increases from low speed to high speed.

Abstract: A system for assisting the linear movement of a pull-out component relative to a housing includes a first bracket coupled to a slide member of the housing, a second bracket coupled to the pull-out component, and a strut that is pivotally coupled to the first and second brackets at its respective ends. The strut includes an outer hollow member that houses a primary spring, a cylindrical piston that translates through one end of the outer hollow member, and a reverse damping mechanism. A free end of the primary spring is held inside the outer hollow member by a clevis for the first bracket, and its opposite end rests on the piston. The piston's free end includes a clevis for the second bracket. An inner hollow member houses a second spring which regulates movement of a damper shaft such that damping occurs when the shaft is pulled out of the damper.

Abstract: A door closer, in particular a hinge door closer, having a free-swing function, including a door closer housing, an output shaft to be connected to a door, a piston assembly connected to the output shaft and guided in the door closer housing, a closer spring, a piston rod adapted to connect the piston assembly to the closer spring, a free-swing assembly which is adapted to enable a translational motion of the piston assembly decoupled from the closer spring when the closer spring is locked, and which is embodied as a sliding-coupling which exclusively transmits compressive forces between the closer spring and the piston assembly, and a hydraulic lock compartment adapted to lock the closer spring.

Abstract: A door closer comprises a spindle journaled in a housing and connected to turn with a door. Upon rotation of the spindle, a cam carried by the spindle effects linear movement of a slide assembly relative to the housing. A piston is connected with the slide assembly. Passages are provided in the housing to permit flow of fluid in the housing in response to movement of the piston. A spring assembly disposed outside of the housing is connected to the piston. Rotation of the spindle and cam during door opening moves the slide assembly, thereby compressing the spring assembly for storing energy for urging the piston and the slide assembly in the opposite door closing direction.

Abstract: A door closer comprises a spindle journaled in a housing and connected to turn with a door. Upon rotation of the spindle, a cam carried by the spindle effects linear movement of a slide assembly relative to the housing. A piston is connected with the slide assembly. Passages are provided in the housing to permit flow of fluid in the housing in response to movement of the piston. A spring assembly disposed outside of the housing is connected to the piston. Rotation of the spindle and cam during door opening moves the slide assembly, thereby compressing the spring assembly for storing energy for urging the piston and the slide assembly in the opposite door closing direction.

Abstract: A door closer includes an anchor assembly for mounting on a door frame, an actuator assembly for mounting within the thickness of a door which is hinged for movement between open and closed positions, an operating member coupled by a linkage to the anchor assembly and mounted for a range of movements between a retracted position and an extended position, a resilient driving apparatus arranged to exert a driving force on the operating member, a damper mechanism operatively connected to the operating member so as to damp movement of the operating member at least in a direction towards the retracted position, and a resilient thrust device arranged to exert an increased driving force on the operating member over a defined part of its range of movement as the operating member approaches the retracted position.

Abstract: A door closer having a pair of main driving springs, a fluid-filled damper arrangement and a pair of thrust springs is provided, the thrust springs coming into effect during the latter part of a door closing operation, so as to provide an augmented closing force at that point. The position at which the augmented closing force is applied is variable, with a cam mechanism being used to control application of the increased closing force.

Abstract: A door closer comprises an actuator assembly (20) adapted for fitting within the thickness of a door and an anchor member (10) adapted for fitting in a door frame in opposed relation to said edge face of the door. An operating member (30) is driven by spring means (45) and coupled to said anchor member (10) to draw the door towards the door frame. An adjustable fluid-filled damper (50) is coupled to said operating member (30) and arranged to provide variable regulation the rate of movement of the operating member under the force of said spring means (45). Resilient thrust means (85) are arranged to exert an increased driving force of said operating member (30) and adjustable control means (100) are provided whereby said thrust means (85) is operative to augment the driving force to said operating member (30) over a defined but variable part of said range of movement corresponding to movement of the door over the final part of its movement into its closed position.

Abstract: A door closer with an oblong, one-piece body such to achieve a compact and aesthetic unit which can be produced with a minimum material consumption. The door closer has lateral faces which each have a curvature and/or bevel that shapes towards each other, which curvature or bevel starts at the lower surface and ends at the upper surface of the door closer. The door closer also has bearing blocks that are built between their fronts and the lateral faces ascending from the body's lower surface.

Abstract: A valve element for operative association with a valve seat in a passage in a body in which the valve element is mounted, in use, the valve element comprising first and second portions connected together by snap-fit means, the first portion being screw-threaded for mounting it in said body, and part of the second portion interrupting said screw-thread of the first portion.

Abstract: A door closer for hingedly mounted doors comprises an actuator adapted for fitting within the thickness of a door and an anchor member adapted for fitting in a door frame such that when installed the closer acts to draw the door into a position of closure at a rate controlled by a fluid-filled damper which comprises a cylinder containing hydraulic fluid, a piston slidable longitudinally of said cylinder and dividing the cylinder into two chambers and a flow restriction assembly associated with the passageway incorporated in said piston to limit the rate of flow of hydraulic fluid from one chamber to the other when the piston is moving in the door-closing direction. The flow restriction assembly defines a flow-restricting passageway including a slot and to enable to flow restriction imposed on the hydraulic fluid to be adjusted when the door closer is installed and in use, the effective length of the slot is variable by relative positional adjustment of two elements by which the slot is defined.

Abstract: A door damping system includes a base fixed to a wall, a fixing element fixed to the door and a rod connected between the base and the fixing element, the base having a pinion rotatably disposed in the base and the pinion coupled to the rod and a coil spring, a cylinder having a slidable piston rod which has a first end with a rack which is slidably received in the base for an engagement with the pinion and a second end with a piston slidably disposed in the cylinder in which oil is filled, the piston having a first and a second flanges, the first flange having a gap defined between the first flange and an inner periphery of the cylinder, the second flange having a plurality of fifth holes defined therein and a first clearance being defined between the piston and the piston rod, a ring movably disposed between the first and the second flanges so as to seal the gap when the door is returned and oil can only flow through the first clearance so as to slow down the speed of returning of the door.

Abstract: A door closer includes a body having a closed, fluid-filled cylinder. A piston is slidably mounted in the cylinder and has an actuating rod with rack gearing. A pinion is rotatably mounted on the body for meshing with the rack gearing of the actuating rod to axially move the piston. The closer also has a valve that can bypass fluid past the piston to regulate its motion. A spring mounted outside the cylinder can apply a balanced, substantially axial force to the actuating rod for axially urging the piston.

Abstract: Hydraulic door closer apparatus comprises a cylinder, a piston disposed in the cylinder, linkage means coupled to the piston for transmitting forces between the piston and a door, and a hydraulic circuit for controlling movement of the piston in the cylinder. A temprature responsive control element is provided in the hydraulic circuit to alter the characteristics of the circuit in response to changes in ambient temperature or temperature of the fluid within the closer.

Abstract: Hydraulic door closer apparatus comprises a cylinder and an elongated piston disposed in the cylinder, the piston being made of relatively easily machined material, but having associated with it a rack of harder, wear and impact-resistant material for transmitting forces and motion to and from the piston.