Abstract: A damper for fittings for furniture or household appliances has a housing in which a piston connected to a piston rod is guided in a linearly displaceable manner, the piston dividing an interior space in the housing into two chambers, wherein at least one flow channel is formed on or in the piston, which flow channel connects the two chambers to one another, wherein a throttle element is provided, which, in a damping position, keeps the cross-section of the at least one flow channel small when the piston moves in a first direction in order to generate high damping forces, and when the piston moves in the second direction opposite to the first direction, increases the cross-section of the at least one flow channel for reducing the damping forces by a movement of the throttle element.

Abstract: A system for monitoring safety-relevant functions of a door closer for the leaf of a door being used in particular as a fire protection barrier, of a window, or the like comprises a sensor system associated with the door closer for detecting predefinable operating variables of the door closer and a control and/or evaluation device connected to the sensor system for monitoring compliance with predefinable safety functions of the door closer on the basis of the operating variables detected by the sensor system.

Abstract: A damper providing varying damping force is provided. The damper may include a housing and a rotary member rotatably received the housing. The rotary member may rotate within the housing between defined end points of travel to define an angular range of travel of the rotary member. An outermost surface of the rotary member may be spaced inwardly from an inner surface of the housing defined between the end points of travel to define a gap between the outermost surface of the rotary member and the inner surface of the housing throughout the angular range of travel. The gap may vary in dimension depending on a rotational position of the rotary member to provide varying damping rates within the angular range of travel of the rotary member.

Abstract: A hinge hydraulic infinite check structure includes a paddle having at least one hydraulic aperture is rigidly fixed to a shaft. The pivot shaft is supported for pivoting movement within a case. The case includes a wall portion rigidly fixed to a cylindrically shaped inner surface and extends radially inward to the shaft. Pivoting movement of the pivot shaft forces the hydraulic fluid to move through the aperture from a first side to a second side of the paddle generating movement resistance. With the pivot shaft being stationary relative to the fluid chamber, equilibrium of fluid pressure of the hydraulic fluid at the first side and the second side of the paddle imparts a resistance to pivoting movement of the pivot shaft relative to the fluid chamber.

Abstract: A dishwasher includes a washing compartment, at least one dishware container, and a guide assembly to allow the dishware container to be moved out of the washing compartment and into the washing compartment. The movement of the dishware container in relation to the washing compartment is cushioned by at least one damping device which is arranged inside the washing compartment.

Abstract: A damping device that includes an arm having a longitudinally extending slot and a cylinder cut-out defined therein, and a damping assembly secured in the cylinder cut-out. The damping assembly includes a cylinder housing with a chamber having a piston and fluid disposed therein. The piston includes a rod with a head on a distal end thereof that extends outside the cylinder housing and into the slot. The damping assembly includes a biasing member extending between the cylinder housing and the head.

Abstract: A counterbalance assembly for an appliance hinge has a base including first and second spaced-apart side walls and a transverse face wall. A channel is located between the first and second side walls. First and second notch portions are respectively located in the first and second side walls. A rotating cam is supported on the base and has a camshaft that extends between the side walls and that is adapted for rotation about an axis of rotation, a first end located in the first notch portion and a second end located in the second notch portion. A biasing spring has an inner end engaged with the base and an outer end spaced from the base. A spring rod includes an outer end operatively coupled to the spring and an inner end operatively coupled to the lever. The lever also pivotally connects to the lobe of the cam. A damper assembly is connected to the base and having a piston which is moved between a first position and a second position by the lever contacting the piston.

Abstract: A damping device that includes an arm having a longitudinally extending slot and a cylinder cut-out defined therein, and a damping assembly secured in the cylinder cut-out. The damping assembly includes a cylinder housing with a chamber having a piston and fluid disposed therein. The piston includes a rod with a head on a distal end thereof that extends outside the cylinder housing and into the slot. The damping assembly includes a biasing member extending between the cylinder housing and the head.

Abstract: The present invention relates to a mechanism for closing a hinged member which comprises a resilient element for effecting closure of the hinged member and a hydraulic damper 5. The hydraulic damper 5, comprising a closed cylinder cavity 20 within a cylinder barrel 19, a rotational damper shaft 22 which extends into the cylinder cavity 20, and a piston 21, placed within the cylinder barrel 19 so as to divide the cylinder cavity 20 into a first side 20a above the piston 21 and a second side 20b below the piston 21. An outer perimeter surface of the piston 21 presents a clearance fit with an inner perimeter surface 27 of the cylinder barrel 19 at 20° C. The cylinder barrel 19 is made of a first material and the piston 21 of a second material which has a higher thermal expansion coefficient than the first material. In this way variations of the viscosity of the hydraulic fluid as a result of pressure fluctuations are compensated for by an increase or a decrease of the cross-section area of the clearance.

Abstract: The present invention relates to an actuator (1), comprising an output member (6); a resilient element (8) connected to said output member (6) so as to urge it in a first direction; and an hydraulic rotation damper (5) with a closed cylinder cavity, a rotational damper shaft which extends into the cylinder cavity, and a piston dividing the cylinder cavity into a first side and a second side. Within the rotation damper (5), the rotational movement of the damper shaft is converted into a translational movement of the piston along a longitudinal axis of the shaft. A restricted fluid passage communicates said first and second sides. The damper shaft is connected over a gearing (10, 15, 17) to the output member (6) and resilient element (8) of the actuator for damping movement of said output member (6) in said first direction. The present invention relates to both rotational and linear actuators as well as to a closing mechanisms for hinged members, such as doors, gates, or windows, comprising such actuators.

Abstract: A damped spring hinge is disclosed, which includes a shaft seat, a shaft, a sleeve, a sliding member, an elastic unit, a non-return valve, a throttle valve. The shaft seat has a seat body, wherein a shaft hole and a receiving hole are formed in the seat body. The shaft can be rotatably disposed in the shaft hole. The sleeve is received in the receiving hole. The sliding member can be slidably disposed in the sleeve. An oil reservoir is formed by the sliding member and the sleeve. The elastic unit is disposed in between the sleeve and the sliding member. The non-return valve is disposed in the oil reservoir, and the throttle valve is disposed on the seat body. Thereby, a self-closing action for the door can be generated, along with the damping effect by the hydraulic oil. A control device of the damped spring hinge is also disclosed.

Abstract: A door closing mechanism which includes a hydraulic rotation damper, having a closed cylinder cavity within a cylinder barrel, a rotational damper shaft which extends into the cylinder cavity, a piston dividing the cylinder cavity into a first side above the piston and a second side below the piston, a one-way valve allowing fluid flow from said first side to said second side of the cylinder cavity, and a fluid passage between said first and second sides of the cylinder cavity, with a flow restrictor, in particular in the form of a needle valve, adjustable through an orifice in the cylinder barrel, wherein said second side of the cylinder cavity and said orifice are at opposite sides of the flow restrictor.

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 hydraulic solenoid control valve, including a valve housing, a valve chamber, having a first valve seat bore as a connection to a first line, a second valve seat bore as a connection to a second line, and a free aperture to a third line, a solenoid, and a valve spindle movable by the solenoid and partially arranged in the valve chamber. The valve spindle includes, a first sealing surface facing the first valve seat bore and a second sealing surface facing the second valve seat bore. The first and the second valve seat bores can be closed. The valve spindle protrudes from the valve chamber through the second valve seat bore toward the solenoid. When the second valve seat bore is closed, the valve spindle is pulled into the second valve seat bore by a differential-area-ratio through the pressure in the second line.

Abstract: The present invention relates to a mechanism for closing a hinged member which comprises a resilient element for effecting closure of the hinged member and a hydraulic damper 5. The hydraulic damper 5, comprising a closed cylinder cavity 20 within a cylinder barrel 19, a rotational damper shaft 22 which extends into the cylinder cavity 20, and a piston 21, placed within the cylinder barrel 19 so as to divide the cylinder cavity 20 into a first side 20a above the piston 21 and a second side 20b below the piston 21. An outer perimeter surface of the piston 21 presents a clearance fit with an inner perimeter surface 27 of the cylinder barrel 19 at 20° C. The cylinder barrel 19 is made of a first material and the piston 21 of a second material which has a higher thermal expansion coefficient than the first material. In this way variations of the viscosity of the hydraulic fluid as a result of pressure fluctuations are compensated for by an increase or a decrease of the cross-section area of the clearance.

Abstract: A multiple position ball stud assembly for a closure strut supporting a closure pivotally attached adjacent to an opening, and a method of operation, is disclosed. The ball stud assembly may comprise a ball stud and a ball stud actuator. The ball stud may have a socket portion mounted on a closure lift assist strut and a guide pin extending from the socket portion. The ball stud actuator assembly may include a housing, a guide for receiving the guide pin, and an actuator for moving the guide pin along the guide to thereby cause the ball stud to move relative to the housing. The multiple position ball stud assembly may also include a control assembly that engages the actuator for selectively causing the actuator to move the guide pin along the guide.

Abstract: A spring hinge comprises a frame leaf, door leaf, upper and lower tube sections to fixedly connect with frame leaf, and middle tube section to fixedly connect with door leaf, wherein middle tube section is internally made with a hydraulic damping speed reducing device; lower tube section is internally installed with a torsion spring device, wherein torsion spring being completely sleeved on the exterior of spindle rod is affixed to the spring seat at the lower end thereof, and an upper and lower clutching device is installed between middle tube section and torsion spring device thereby allowing middle tube section and torsion spring device to be separated or combinedly moved, wherein torsion spring and hydraulic damping speed reducing device are packagely used to close door slowly while releasing spring energy after closing to set angle to precisely close the door.

Abstract: A door closing mechanism which comprises a hydraulic rotation damper 5, comprising a closed cylinder cavity 20 within a cylinder barrel 19, a rotational damper shaft 22 which extends into the cylinder cavity 20, a piston 21 dividing the cylinder cavity 20 into a first side 20a above the piston 21 and a second side 20b below the piston 21, a one-way valve 33 allowing fluid flow from said first side 20a to said second side 20b of the cylinder cavity 20, and a fluid passage 31 between said first and second sides 20a,20b of the cylinder cavity 20, with a flow restrictor, in particular in the form of a needle valve 32, adjustable through an orifice in the cylinder barrel 19, wherein said second side 20b of the cylinder cavity 20 and said orifice are at opposite sides of the flow restrictor.

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: Disclosed is a door damper, in which a safety check valve is installed in consideration of the case in which an impact exceeding a design pressure will be applied, thereby absorbing the impact to enable a door to be closed safely and smoothly. In the door damper, a safety check valve is installed in a piston, and thus is opened in cooperation with another check valve installed between a spring holder and the piston when the pressure exceeding a design pressure is applied. Thereby, when the impact exceeding the design pressure occurs, the safety check valve can absorb the impact to prevent damage. A channel can be adjusted by only ridges formed on an outer circumference of the check valve, so that productivity can be improved thanks to easy tolerance management. Further, an oil seal is not contracted or deformed in spite of long-term use.

Abstract: The invention relates to door closers, particularly a door closer control device that regulates the flow of a pressure medium controlling the function of a door closer. A control device according to the invention includes a support part with a collar that serves as a second support for the control device on the door closer body in addition to the support in the guiding part. This second support holds the control device in place within the pressure medium flow without any rocking or swaying movement, which would hamper the door closing speed.

Abstract: A drive device for opening or closing a leaf of a door, a window or similar includes a housing and a closing spring, which is located in the housing and acts upon a piston, the latter co-operating with a closing shaft in the housing by means of gearing, The piston and housing are made of injection molded polyoxymethylene plastic (POM).

Abstract: An example furniture hinge includes a saddle supporting the damping cylinder that engages a first mounting edge of the supporting arm from behind. A locking element supported movably on the saddle has a laterally protruding mounting lug, which in a locking position engages a second mounting edge of the supporting arm from behind. The second mounting edge is oriented counter to the first mounting edge.

Abstract: A door closer comprising: (a) a housing for fitting into a door, the housing having a mounting plate with an opening adjacent to a central bore of the housing; (b) a tension member extending longitudinally within the central bore of the housing and extending outwardly of the housing through the opening to define an end thereof for fitting to a door frame; (c) a movable body within the housing and adapted for longitudinal movement within the central bore, the movable body being connected to the tension member; (d) a spring within the housing and biasing the movable body in a first direction away from the mounting plate so as to urge the tension member inwardly of the housing in a door closing motion; and (e) a hydraulic damping assembly for damping the longitudinal movement of the movable body at least in the first direction, the hydraulic damping assembly being disposed within the central bore of the housing, wherein the hydraulic damping assembly comprises a piston, coupled to the housing by a piston shaf

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: This invention relates to an overhead door closer with slide arm assembly having a toothed pinion that is eccentrically supported and presents a circular rolling curve, which pinion meshes with a toothed rack arranged at a piston. The invention concentrates on a particular embodiment of the rolling curve and of the teeth of the toothed rack in adaptation to a toothing of the pinion. Furthermore, the invention concentrates on an improved embodiment of the delayed closing operation in order to achieve an optimized movement pattern of the piston within the housing of the overhead door closer with slide arm assembly.

Abstract: A door closer comprising a housing, a member for driving engagement with a door, the member being rotatable relative to the housing in a door opening direction and in a door closing direction, a spring apparatus within the housing providing a resilient bias, the resilient bias being increased by rotation of the member in the door opening direction and a check device for controlling rotation of the member in the door closing direction and hence closure of the door under the action of the spring apparatus, the door closer having a back check comprising a piston member movable in a cylinder from an initial position against resistance of a fluid medium by rotation of the rotatable member in the opening direction.

Abstract: A readily adjustable door closure for varying the rate of speed at which an associated door may close which is effected by rotating the piston rod relative to the piston and associated cylinder assembly so as to vary the rate of flow of an actuating fluid flowing from one side of the piston to the other side of the piston, which controls the door closing speed accordingly.

Abstract: A door closer includes casing fixedly fastened to a door frame, a hydraulic cylinder installed in the casing and holding a hydraulic fluid, a coupling block installed in one end of the hydraulic cylinder, the coupling block having a pivot shaft connected to a door, and a reciprocating mechanism coupled to the coupling block, fluid velocity regulating valves installed in the casing and controlled to adjust the velocity of the hydraulic fluid flowing in the casing, the reciprocating mechanism including a double-threaded adjustment rod for adjusting the spring power of compression springs thereof.

Abstract: The invention describes a door closer with an energy storage that includes a resisting spring (3), with a closer shaft (1) driven by the resisting spring (3) and with an hydraulic fluid damped damping device (12, 13), whereby the energy storage and the damping device (12, 13) act upon a common closer shaft (1), whereby the resisting spring (3) and the closer shaft (1) are not in contact with the fluid of the damping device (12, 13). In this way a particularly slim housing is possible.

Abstract: An improved door closer includes a base fixedly provided on an inner side of a door, and a link member. The inner side of the base is provided with a piston. The piston is biased by a release member, and has a connecting block and left and right end blocks extending upward from two ends of the connecting block. The bottom portion of the connecting block is provided with a guide groove in the same direction as a long axis of the base. The right end block is recessed inward to form an insert groove. A roller is pivoted in the insert groove. A transmission shaft passes through the guide groove of the piston. The intermediate portion of the transmission shaft is provided with a cam abutting against the roller. When an external force pushes open the door, the cam is rotated to cause the piston to bring the release member into a compressed state.

Abstract: A hydraulic backcheck valve system for controlling an opening cycle of a door closer has a housing with an interior chamber, at least one cylinder, and a piston that can reciprocate between a door closing stroke and a door opening stroke within the cylinder. One side of the piston faces a variable volume chamber in the cylinder and an opposite side of the piston faces the interior chamber of the housing. The backcheck valve system has a fluid passage with a port in fluid communication with the cylinder and an opening in fluid communication with the interior chamber of the housing. The port is blocked by the piston during at least part of the door opening stroke. A one-way valve is disposed in fluid communication with the fluid passage and permits fluid to flow freely during a closing cycle of the door closer and prevents fluid flow from the second passage during the opening cycle. A backcheck valve is disposed in fluid communication with the passage and with the variable volume chamber.

Abstract: A door closer includes a cylinder and a piston sliding along the cylinder with a piston rod extending from the cylinder, with the closer mounting at one end to the door and at a second end to the door frame. The door closer has a speed adjustment know extending from a first end for varying the closure rate. Adjustable mounting brackets provide for flexibility in mounting configurations and closing force. A door lock maintains the piston in an extended position and keeps the door open. The lock includes a washer sliding on the piston rod in a first position and locking the rod at a second position. The washer has a tab that engages an angled surface in the first position to prevent locking engagement with the piston rod. A rotatable end cap rotates the washer between the locked position and the unlocked position.

Abstract: A resilient member, useful in a back checking arrangement, is provided as a body of resilient material having a surface engageable by an outside member such as a portion of a sliding mechanism in a door closer. The body is compressible when engaged by the outside member with a sufficient force. The body has at least one reservoir chamber therein, for receiving a liquid, such as hydraulic fluid, with a communication passage leading from the chamber to the surface to provide fluid communication between the chamber and an exterior of the body. Additional communication passages from the chamber to the exterior of the body may be provided as well. When the body is engaged by the member, the body, chamber and passage are compressed, thus causing the liquid in the chamber to exit the body through the compressing passage. This increasingly restricts the flow of liquid through the passage and increases the force of operation.

Abstract: A damper assembly (50) adapted to a reciprocative door closer device (10) and contingent door (62), the device (10) comprising a piston rod (16) which functions reciprocatively from within a piston body (12) controlling a biasing means (11); the rod (16) normally loosely mounted with a checking mechanism (22) for variably holding both the rod (16) in an extended position (16-B) and a door (62) in an open position (62-B); the assembly (50) comprising a fixated bracket (50-A) with an offsetting fastener means (52) for universal attachment to left and right hinging doors (62), and, similar to the reciprocative device (10), the assembly (50) comprising an extensible bracket (50-A) controlling a counter biasing means (55) by use of an operator (54) selected from a group including a spring operator means (54-A) that acts to dampen, counter, and protect the device (10) and the door (62) from damage due to excessive inward biasing forces (11-B), and, acts to compensate for a superior checking mechanism (22) such as w

Abstract: A door closer with a door piston, which door piston is acted on by a driven shaft during the opening of a door. The door piston has an extension attached to it. The door closer also can have a pressure piston and an energy storage mechanism which acts on the pressure piston. The pistons can be axially guided and can interact with hydraulically connected pressure chambers to connect and disconnect the pistons during the opening and closing of the door closer.

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: An automatic revolving door drive is described, with a hydraulic piston-cylinder unit with a closing spring and an opener motor, consisting of an electric motor and hydraulic pump. It is a so-called servo closer, with which the door is opened with motor support and automatically closes with hydraulic damping under the influence of the closing spring.In order to be able to use even low-powered opener motors and to produce a relatively compact design, provision is made such that during the motorized opening process the pressure of the hydraulic medium is regulated with adjustment to the prevailing force of the closing spring, in which the closing spring that cooperates with the piston abuts the piston at one end and a hydraulic pressure cushion at the other end, with the same hydraulic pressure being set and regulated by a special pressure-regulating valve in the pressure chamber and in the hydraulic pressure cushion.

Abstract: An improved multi-stage door closer for automatically closing a door after the door is opened, is disclosed. It contains a cylinder having three sections each with a different diameter, with the middle section having the largest diameter. A pair of speed adjusting mechanisms are provided which are sleeved about a piston rod placed inside the cylinder. Each of the speed adjusting mechanism contains a rotatable piston head, which will rotate with the cylinder, and a fixed piston head, which will not rotate with the cylinder. In a preferred embodiment, the rotatable piston head contains a radially extending groove in communication with an axially extending graded groove, and the fixed piston head contains a spiraled or serpentined O-ring that cuts across the axially extending graded groove.

Abstract: A hydraulic control system for automatically closing and opening a door is disclosed and has means for providing such opening and closing even if power is lost to the hydraulic control system. Further disclosed is a fluid control device of the hydraulic system which prevents the door from being opened or closed too quickly that might otherwise harm an individual that comes into the path of the moving door.

Abstract: A door stop including an hydraulic cylinder connectable to one of a door assembly part, a stop piston longitudinally displaceable in the hydraulic cylinder and connected with another part of the door assembly by a piston rod, and two spring-biased closing pistons located in two separate conduits formed in the stop piston for communicating two, spaced by the stop piston, pressure chambers formed in the cylinder, with a limited length conduit being formed in the hydraulic cylinder and by-passing the stop piston for directly communicating the pressure chambers.

Abstract: A check or stop for a moveable member, the check or stop comprising actuated means actuated by the moveable member, or alternatively by seperate actuating means, the actuated means being either fastened with the moveable member or being integral with the moveable member, automatic switching means to control the checking and release of the actuated means and the moveable member, the moveable member being moveable from a first state, wherein the moveable member is substantially static, checked, and exhibits a first value for a predetermined characteristic of the actuated means, to a second state wherein the moveable member is substantially in motion, unchecked, and exhibits a second value of the predetermined characteristic of the actuated means, the value of the predetermined characteristic of the actuated means being available to the automatic switching means, wherein when the moveable member is in a static state the first value of the predetermined characteristic available to the automatic switching means pr

Abstract: A control for a power-assist feature for an hydraulic closer is driven by structure mounted on the pinion shaft of the closer. It includes a pump-activating arm slidably mounted on the shaft, the end of the arm adapted to cover a pump-on sensor when the door is `bumped`. It also includes a follower rotatably mounted near the pinion and engageable escapement-fashion by a wheel in friction fit on the pinion shaft, the follower carrying a pump-deactivating arm, the end of the latter arm adapted to move away from a pump-off sensor when the door opens to its preset limit.

Abstract: A quick release door closer including a hydraulic assembly and a spring assembly connected at a quick release connection. The quick release connection includes a retaining element and element housing structured to allow the door closer to be easily maintained and, if necessary, the hydraulic assembly to be easily removed and replaced.

Abstract: A door closer has a fluid conduit connecting the high pressure portion of the cylinder in front of the piston with a cavity between the surfaces of the cylinder wall and the piston. This cavity is located at the intermediate lateral surface of the piston at the back side of a gear rack formed on the piston. The variable lateral bias provided by the pressurized cavity counteracts separating forces between the gear rack and a gear pinion caused by the tapered teeth. This decreases friction between the piston and the cylinder and reduces wear throughout the closer mechanism.

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: To simplify the fabrication of the housing of an automatic door closing device with hydraulic damping, it is proposed to configure the housing as a tubular hollow cylinder 106 on which, externally, by means of one or more compactly superimposed covering elements 102, a bypass valve 121 is formed.

Abstract: A rotary damper is disclosed having a hollow casing and a power receiving shaft extending exteriorly of the casing. The power receiving shaft turns a movable vane within the casing to pressurize a working fluid. A stationary partition member including a dividing wall and a dividing vane is positioned within the casing and journals the movable vane for rotation within the casing. The movable vane is provided with a through hole equipped with a one-way valve and the dividing wall is provided with a plurality of arcuately spaced orifices. The orifices are positioned to be serially covered by the movable vane as it is rotated to thereby provide increased resistance to fluid flow as the movable vane is further rotated.

Abstract: An improved door closer is provided which has a back checking arrangement including a loosely held resilient cushion bar which is engaged by a metallic shield abutting sliding cam plates during a final few degrees of opening of a door to provide an increasing resistance against further opening of the door. The shield preferably engages the cushion bar approximately 4.degree. prior to a normal full open position of the door. Selective thickness of the cushion bar provides either a 90.degree. full open position of the door or a 150.degree. full open position of the door without additional adjustment.

Abstract: An automatic door closer includes: a casing having a primary and a secondary cylinder juxtapositionally formed in the casing for resiliently holding two pistons in the two cylinders filled with a hydraulic oil and partitioned with a wall formed with a main hole and a throttling hole for communicating the two cylinders, wherein each piston is normally urged by a tensioning spring towards the two holes in the casing, whereby upon an opening of the door, an upper piston is retracted to compress an upper spring in the primary cylinder to suck oil from the secondary cylinder to the primary cylinder and also to extend the lower piston and tension the lower spring for accelerating a door opening operation and saving the door-opening force; and a positioning device provided for temporarily keeping the door at its opened state by locking a positioning pin in a recess formed in the upper piston.