Abstract: Disclosed are systems and devices for controlling the closing of a door. A head unit is to be installed in a doorjamb, comprising a chamber filled at least in part with a shear thickening fluid. A piston is connected to a cap and configured to exert pressure against the shear thickening fluid in response to a force applied to the cap. The systems and devices provide an adjustable design that resists door slamming and aggressive closure, serving as a safety device as well as noise, damage and pet control around doors (preventing closure if desired). An install kit provides exact location, depth control and guide to place over the head unit to tap it into place with a hammer.

Abstract: A machine tool includes: a cover; a door; a drive mechanism; a detection unit; and an operation panel that receives an operation for the machine tool. A control device of the machine tool performs: processing to control the drive mechanism such that the door is opened, based on the operation panel receiving a first opening operation; processing to obtain an actual position from the detection unit and store the actual position as an opening position of the door, based on the operation panel receiving an operation to determine a position; and processing to control the drive mechanism such that the door is located at the opening position, based on the operation panel receiving a second opening operation. An opening speed of the door during the first opening operation is slower than an opening speed of the door during the second opening operation.

Abstract: A cam action door closer comprising a body, a spring, a speed control channel system and a latching control channel system, a closing control piston having a piston head and a circular side. The closing control piston has a cutting on the side of the closing control piston and on the piston head, the cutting forming a control edge at its end. The cutting has a length between the piston head and the control edge. The speed control channel system comprises a speed connecting channel, which is located in such a way that the control edge is arranged to close it.

Abstract: This disclosure is generally directed to a hydraulic door closer, and more specifically is directed to a hydraulic storm or screen door closer that has a fluid overflow chamber providing fluid volume and pressure control for both expanded and contracted fluid at different temperatures. The disclosed hydraulic door closer comprises a fluid overflow chamber adapted to hold sufficient fluid to maintain required operating fluid or oil levels at different temperatures, and to ensure proper closer performance under both extreme high and low temperature conditions.

Abstract: This disclosure is generally directed to a hydraulic door closer, and more specifically is directed to a hydraulic storm or screen door closer that has a fluid overflow chamber providing fluid volume and pressure control for both expanded and contracted fluid at different temperatures. The disclosed hydraulic door closer comprises a fluid overflow chamber adapted to hold sufficient fluid to maintain required operating fluid or oil levels at different temperatures, and to ensure proper closer performance under both extreme high and low temperature conditions.

Abstract: The invention relates to a brake disk lock comprising a brake disk detection device, a sensor for detecting a positional change of the lock, an alarm module that is configured to output an alarm when the sensor detects a relevant positional change of the lock, an unlocking motor for unlocking the lock, an authentication module for a wireless authentication of a user of the lock, and an actuation element that can be actuated by the user and by means of which the authentication module can be activated. A further subject is a locking system comprising such a lock and a mobile end device by means of which a user of the brake disk lock can authenticate himself thereat. The invention further relates to a method of unlocking a brake disk lock.

Abstract: The present invention relates to a hinge device for a rotating door, and more particularly, to a hinge device for a rotating door, which is mounted on the rotating door so that the door can be opened and closed while rotating in various ways. The hinge device for the rotating door of the present invention rotates by an external force and then rotated in a free stop manner at a certain section, and automatically rotates in a reverse direction at a section where the hinge device reversely rotates after free stop rotation.

Abstract: A closing device includes an actuator mechanism and a hydraulic damper mechanism. The actuator mechanism includes a pushrod urged by a resilient member towards its extended position. The hydraulic damper mechanism includes a piston, a first rack and pinion gearing for converting the translational motion of the pushrod into a rotational motion of a first pinion, a transmission, which includes a second rack and pinion gearing, between the first pinion and the piston for transmitting and converting the rotational motion of the first pinion into a translational motion of the piston, a one-way valve allowing fluid flow from a first side to a second side of the cylinder cavity when opening the hinged member, and a restricted fluid passage between the first and second sides of the cylinder cavity.

Abstract: A spring balanced support device having at least one arm, connected to its surroundings via a movable pivot point, forming an arm mechanism to which a mass may be coupled directly or indirectly at a mass coupling point, balanced by at least one spring, at one end directly or indirectly connected to the arm mechanism at a spring connection point, the other end directly or indirectly connected to the surroundings at a spring base point, wherein the spring base point is located substantially on an axis which extends through the movable pivot point and substantially parallel to a direction of a force exerted on the spring balanced support device at the mass coupling point due to the force of gravity on the mass, or wherein the spring base point is located at a distance from said axis along a line which intersects the axis and which extends substantially parallel to a pivot point axis of the movable pivot point, wherein the movable pivot point is movable along the axis in order to adjust the spring balanced suppor

Abstract: Disclosed is a door closer that can easily adjust the spring force of a return spring. A piston 2 moves toward a first oil chamber 15 upon a door opening operation and moves toward a second oil chamber 16 upon a door closing operation. A return spring 50 is located on the same line as the piston 2. The return spring 50 is interposed between a spring retaining seat on a fixed side close to a main shaft 3 and a spring retaining seat on a moving side distant from the main shaft 3. The return spring 50 is compressed by the spring retaining seat on the moving side moving closer to the spring retaining seat on the fixed side upon the door opening operation and then stores the closing force.

Abstract: A door closing device having a housing, a lever interface for the attachment of a door closing mechanism (110), which interface is rotatably supported in the housing, a spring device, which charges the lever interface with a closing torque, and a dampening device for dampening the charging of the lever interface with the closing torque, where the housing is configured, at least in sections, as a cold-deformed structural member.

Abstract: A hinge device for rotatably moving a closing element includes a fixed element anchorable to a stationary support structure coupled to a movable element anchorable to the closing element for rotating around a first longitudinal axis between an open position and a closed position. The device further includes at least one slider movable along a second axis between a compressed and an extended position. One between the movable element and the fixed element includes at least one operating chamber defining the second axis so as to slidably house the slider, the other element including a pivot defining the first axis. The pivot and the slider are reciprocally coupled so that to the rotation of the movable element around the first axis corresponds the sliding of the slider along the second axis and vice versa.

Abstract: The instant disclosure relates to a door damping apparatus for connecting to a door and an immobile frame. The door damping apparatus includes a shaft seat, a shaft, a cylinder, a piston, a spring unit, a check valve and a throttle valve. The interior of the shaft seat is formed with a fluid passage and a reservoir to store hydraulic fluid. The throttle valve projects into the fluid passage to adjust the flow of the hydraulic fluid, thus allowing the door to be opened smoothly and gently self closes.

Abstract: A hinge device for rotatably moving a closing element includes a fixed element anchorable to a stationary support structure coupled to a movable element anchorable to the closing element for rotating around a first longitudinal axis between an open position and a closed position. The device further includes at least one slider movable along a second axis between a compressed and an extended position. One between the movable element and the fixed element includes at least one operating chamber defining the second axis so as to slidably house the slider, the other element including a pivot defining the first axis. The pivot and the slider are reciprocally coupled so that to the rotation of the movable element around the first axis corresponds the sliding of the slider along the second axis and vice versa.

Abstract: A door closure apparatus with boost for latching a door to which the apparatus is attached. The door closure includes two pivotal arms, an outer covering and an elongated housing. In the housing are a main piston with a rack to engage a pinion connected to rotate with one of the pivotal arms, a piston rod, a main spring, a divider wall, an adjustable main spring seat, a supplemental piston and a supplemental spring. The housing is filled with hydraulic fluid and is divided into three chambers with ports and passageways to move fluid during door opening, which stores energy in both the main and the supplemental springs, and door closing, which begins with energy from the main spring and latches with a boost of energy from the supplemental spring.

Abstract: A door closer with an automated calibration mode is disclosed. The door closer that can be self powered and includes a control unit to intelligently control a valve within the door closer to vary the operating characteristics of the door closer as needed. The control unit includes a calibration mode that can be invoked to match the control unit to the mechanical door closer assembly. A plurality of positional values being output encoders coupled to an arm of the door closer and the motor for the valve can be determined. The positional values from the encoders and the positions that they indicate can then be stored in a memory within the controller for use during normal operation of the door closer.

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: A door closer, in particular a hinge door closer, including a locking function or free-swing function, having 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 hydraulic lock compartment adapted to lock the closer spring, and solenoid control valve, in particular a 3/2-solenoid control valve. A closure damping compartment is formed between the door closer housing and the piston assembly on a side of the piston assembly facing away from the piston rod, and wherein the solenoid control valve controls at least the pressures in the closure damping compartment and in the lock compartment.

Abstract: The invention relates to a regulating valve, which is attachable in particular in a bore, executed with a female thread, of a hydraulic door closer. The regulating valve has a body adjoined by a regulating area. The regulating valve also has a thread provided with an anti-rotation element. The thread, including the anti-rotation element, being screwed into the female thread of the bore. In order to provide a regulating valve of a simple design, in which any unwanted adjustment of the regulating valve during operation is excluded, the anti-rotation element of the regulating valve has a plastic material layer at the thread flanks of the thread. The plastic material layer cooperates with the female thread of the door closer.

Abstract: A door closer components include a housing having a mounting plate, a tension member extending longitudinally within the central bore of the housing, a movable body within the housing connected to the tension member, a spring within the housing, and a hydraulic assembly for hydraulically controlling the longitudinal movement of the movable body. The hydraulic assembly is disposed within the central bore of the housing and includes a piston coupled to the housing and slidable in a fluid-filled chamber within the movable body, wherein the piston divides the chamber into two compartments. The piston has a valve mechanism which opens to permit relatively free movement of the fluid from one compartment to the other when the movable body is moved. The valve mechanism of the piston includes a boss fitted to a piston shaft and defining an annular sealing face and a longitudinally extending channel member integral with the boss.

Abstract: A door closer comprises a piston cooperating with a rotating pinion. Upon rotation of the pinion in the door opening direction, the piston moves toward the second end of the housing forcing fluid from a second variable volume chamber through a passage to a first variable volume chamber and compressing a spring assembly for storing energy. The spring assembly urges the piston toward the first end of the housing for forcing fluid from the first variable volume chamber to the second variable volume chamber and rotating the pinion in the door closing direction. A controller controls the position of a valve in the passage based on the sensed angular position of a door and the position of the valve for determining the amount of hydraulic fluid flowing through the valve.

Abstract: A self-adjusting door closer is disclosed. The door closer is self powered and includes a control unit to intelligently control a valve within the door closer to vary the operating characteristics of the door closer as needed. The controller includes a position sensor to determine a position of the door, and at least one input switch to enable user selection of at least one door closer parameter for an installed door closer. The control circuitry is operable to set the valve in response to the user selection of the door closer parameters, and the position of the door, in order to control force exerted by the door closer on the door. A generator can be provided to provide electricity to power the controller and store power to operate the controller.

Abstract: A door closer with a teach mode is disclosed. The door closer that can be self powered and includes a control unit to intelligently control a valve within the door closer to vary the operating characteristics of the door closer as needed. The control unit includes a teach mode that can be invoked at installation time, or any other time, so that appropriate information can be stored in memory regarding an installation configuration, relative jamb position, swing (right or left handed) and other parameters. These values can be accessed by control circuitry in the controller for use in controlling the door closer during operation.

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 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: A hydraulic door closer including an elongated housing, a connection rod extending into the housing, a piston secured at an inner end of the connection rod within the housing and a spring positioned within the housing about the connection rod. A throttle valve and a check valve are formed in the piston and define a throttle-valve fluid passage and a check-valve fluid passage, respectively. Both fluid passages are configured to be open for passing a fluid through the valves and closed to stop the fluid flow. The check-valve fluid passage is larger than the throttle-valve fluid passage and is closed during door closing for restricted fluid flow slowing the door motion. A stopping/holding mechanism includes a piston groove, a rod groove and a positioning pin disposed between the piston and the connection rod. The piston groove is defined by the piston for retaining the entire positioning pin during door opening/closing motion.

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: A cover for either a left-handed or right-handed operating automatic door closer including a body, and a pinion shaft extending from the top of the body, the cover comprising: a housing including a wall and an open rear, the wall having a rear edge and having therein first and second slots, each of the slots extending forward from the rear edge; and a clip including a base complementary to each of the first and second slots, and a flexible hook including a first end connected to the base and a floating second end, the base of the clip being insertable into either one of the slots so that the base substantially fills the one of the slots and the clip is secured to the wall of the housing with the hook positioned inside the housing and opening rearwardly; the housing with the clip inserted into one of the slots being positionable over the door closer with the hook of the clip receiving the door closer; wherein, when the housing is positioned over the door closer, the pinion shaft extends through the first slot

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: A catcher (2) provided in a door frame H? for capturing a striker body 1 moved from a near front side F when a door D? is rotated toward a reference position; a braking device (5); and a linkage device (3) for both are provided. The catcher (2) is provided to be reciprocatingly rotatable between a standby position and a rotated position, captures the striker body (1) at the standby position, and rotates forward to the rotated position. Braking of the braking device (5) is applied to a rotation toward the rotated position of the catcher (2) through the linkage gear member (30).

Abstract: A cover for either a left-handed or right-handed operating automatic door closer including a body, and a pinion shaft extending from the top of the body, the cover comprising: a housing including a wall and an open rear, the wall having a rear edge and having therein first and second slots, each of the slots extending forward from the rear edge; and a clip including a base complementary to each of the first and second slots, and a flexible hook including a first end connected to the base and a floating second end, the base of the clip being insertable into either one of the slots so that the base substantially fills the one of the slots and the clip is secured to the wall of the housing with the hook positioned inside the housing and opening rearwardly; the housing with the clip inserted into one of the slots being positionable over the door closer with the hook of the clip receiving the door closer; wherein, when the housing is positioned over the door closer, the pinion shaft extends through the first slot

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 piston assembly for a door closer includes a piston formed with a mounting hole and a door closer valve installed with clearance in the mounting hole. The door closer valve has a body part with first and second formations at opposite respective ends of the body part for engaging opposite respective sides of the piston and retaining the valve in the mounting hole. The body part is movable in the mounting hole axially of the mounting hole. The first formation is a protruding flange for seating against the piston at the first side thereof around the mounting hole and creating a seal around the mounting hole.

Abstract: The present invention relates to a door closer, in a housing of which is received a sliding cylinder, the sliding cylinder is provided with teeth on an outer periphery thereof for meshing with a gear wheel of a door shaft, a sliding cylinder interiorly formed with inner wall serves to move relative to a piston of a piston shaft. At an end of the piston shaft is provided with an oil-replenishing cylinder that serves to replenish hydraulic oil to the sliding cylinder via a one-way valve.

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 drive system for a moveable wing, especially for a door or a window, is described. The drive system includes at least one energy storage device by whose discharge of energy the wing is moved. The energy storage device is hereby controllable in its energy discharge by means of a control system. The control system has an electrically controllable control element. The motion of the wing is directly or indirectly detected by a sensor, whose output signal is fed into a regulating device, which controls the control element. The regulating device is realized in a way, that the influence of the control element, dependent on the motion of the wing, can change the energy discharge of the energy storage device.

Abstract: A damper for a pivot door has a piston movably received inside the damper and having a first channel and a second channel respectively and selectively communicating with a space full of hydraulic oil, such that the movement of the piston is able to be slowed by the interchange of the communication of the first channel and the space and the second channel and the space. Thus, the movement of the pivot door is slowed.

Abstract: A door control device for use on a non-fire side of a fire-door mounted in a door frame in a fire-door safety installation has a door closer assembly filled with a hydraulic damping fluid and attached to a non-fire side of the fire-door by at least one fastener; a door control arm pivotally connected to the door frame at a first end and to the door closer assembly at a second end; and the hydraulic damping fluid is one of a group of fire resistant hydraulic fluids.

Abstract: A valve for regulating speed of operation of a door closer, includes an elongated hollow tubular body having a closed first end with driving provisions thereon, an open second end, and an orifice in its sidewall adjacent its closed first end; an endplug for a cylinder bore of the door closer, the endplug having an axial port in which the closed first end of the tubular body is rotatably supported and which provides a fluid tight seal about the outer surface of the tubular body; an annular valve seat adjacent the endplug, the seat being fixed against rotation, and having an open portion and a closed portion which provide varying degrees of occlusion of the orifice when the tubular body is rotated; and a seal plate check valve captured against a piston head and occluding an opening therein during closing, the plate also providing a seal about the outer surface of the tubular body near the open second end thereof.

Abstract: A door closing device comprises a piston (12) having at one end a seal (21) which seals the interface between the piston and a housing (10). The seal (21) also acts as a one-way valve and carries a pressure relief valve (37).

Abstract: The door closer is of the kind which acts, for example between a door hinge stile and a hinge jamb and has a body for mounting usually in the stile, from which body a spring-biased tension member extends correspondingly for anchoring to an anchoring point (for example in the jamb), wherein a hydraulic cylinder-piston damper is interposed between the tension member and a biasing spring therefor, the damper being adapted to allow fluid in use to flow restrictedly past the piston when the tension member (12) is moved in door-closing and door-opening directions; characterized in that the cylinder of the hydraulic cylinder piston damper is formed of a plastics material, and the cylinder is resiliently expansible in response to an increase in pressure therein such that the clearance between the piston and cylinder is increased to permit increased flow of fluid around the piston.

Abstract: A door closer (20) is attachable to a door (24) and is formed with a chamber (44) in which a piston element (50) is movable to move fluid from the chamber to a reservoir (82) upon opening of the door. After the door (24) has been opened to a position, for example, of sixty to seventy-five degrees, continued opening of the door causes the fluid to be compressed within the chamber (44) and to be directed only through a back check valve (95) to the reservoir (82). This results in the development of an adjustable "back check" condition to provide a counterforce to the continued opening of the door. The adjustable valve (95) includes a spring biased ball (144), the biasing of which must be overcome by the force of the fluid being compressed in the chamber (44) to allow for fluid to pass through the valve to the reservoir (82).

Abstract: A door closer having a housing defining a fluid containing chamber and a fluid reservoir and including a piston supported in the chamber for movement in one and an opposite direction in response to respective opening and closing movements of a door. A first fluid passageway defined by the housing provides communication between the chamber and the reservoir for the free passage of fluid from the chamber to the reservoir in response to initial movement of the piston in the one direction. A second fluid passageway spaced in the one direction from the first fluid passageway contains a ball check valve spring biased to closed position for resisting the flow of fluid from the chamber through the second passageway to the reservoir. The valve is threadably adjustable relative to the housing to regulate the resistance to fluid flow.

Abstract: A door closer having a return spring for accumulating a recovering force in a door closing direction at the time of opening a door for performing a braking force by a damper at the time of closing the door which comprises a closer body internally containing a mechanism for performing an operation as the damper in a body case, an adjusting arm coupled perpendicularly to a driving shaft for the damper of the closer body to be projected laterally rotatably, a coupling bracket for pivotally securing an upper frame mounting plate directly or indirectly to the end of the adjusting arm via step screws to be horizontally rotatable, and a door mounting arm projected laterally from the closer body for pivotally securing a door mounting bracket to the end of the arm via a step screw to be horizontally rotatable.

Abstract: A door closer (20) is attachable to a door (24) and is formed with a chamber (44) in which a piston element (50) is movable to move fluid from the chamber to a reservoir (82) upon opening of the door. After the door (24) has been opened to a position, for example, of sixty to seventy-five degrees, continued opening of the door causes the fluid to be compressed within the chamber (44) and to be directed only through a back check valve (95) to the reservoir (82). This results in the development of an adjustable "back check" condition to provide a counterforce to the continued opening of the door. The adjustable valve (95) includes a spring biased ball (144), the biasing of which must be overcome by the force of the fluid being compressed in the chamber (44) to allow for fluid to pass through the valve to the reservoir (82).

Abstract: A powered hinge powered by a hot wax linear actuator, which can provide for bi-directional rotation of the hinge as the consequence of sequential and intermittent energizing and deenergizing sequence of the actuator.

Abstract: A damper for a flapdoor that does not show any damping effect when its movable shaft of the damper is rotated with the door in one sense whereas it effectively damps the rotary movement of the flapdoor when the movable shaft is rotated with the door in the other sense, wherein a one-way clutch for engaging or disengaging the movable shaft with a movable member depending on the sense of rotation of the movable shaft to cause a viscous shearing drag in the viscous fluid contained in the damper and a power source constitute so many integral parts of a coil spring. A damper for a flapdoor having such an arrangement can have a simplified configuration as compared with a damper provided with a separate coil spring as power source and a separate one-way clutch and therefore can be realized with reduced dimensions.

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: A door closer of the kind which acts between a door hinge stile and a hinge jamb has a body for mounting usually in the stile, and from the body a spring-biased tension member extends for anchoring to the jamb. A hydraulic cylinder piston damper is interposed between the tension member and its biasing spring, the damper incorporating no unidirectional valve means and instead its piston being undersized relative to the cylinder by an amount predetermined by the viscosity of hydraulic fluid in the damper so as to allow fluid to flow restrictedly around the piston when the tension member is moved in door-closing and door-opening directions.