| 摘要 |
A door closer includes an anchor assembly 10 for mounting on a door frame, an actuator assembly 30 for mounting within the thickness of a door providing a concealed door closer. The actuator assembly includes an operating member 22 coupled by a link 20 to the anchor assembly and mounted for movement between a retracted position when the door is closed and an extended position when the door is opened. A damper mechanism regulates the closer speed of the door under the action of a resilient biasing force, such as compression springs 45, which biases the operating member in the retracted position. The damping mechanism comprises a cylinder containing fluid divided into first and second chambers 66, 65 by a piston 51. During normal closure of the door, fluid flows from a first chamber 66 to a second chamber 65 via a fluid channel (70, fig.3). A holding mechanism 110 comprising an electrically operated valve is provided which when operated prevents fluid flow from the first chamber 66 to the second chamber 65 and prevents the bias mechanism 45 from driving the operating member toward the retracted position. Whilst the holding mechanism is active the door is not biased closed but instead the door can be freely moved. When deactivated the valve member is preferably biased into the open position. An electromagnet may retain a trigger member against the force of the valve bias to close the valve. A resilient thrust device 90, e.g. leaf spring acting a direction perpendicular to the direction of the operating member, may be provided to exert an additional closing force as the door approaches the closed position. During movement of the operating member to the extended door open position the leaf spring may rise out of a recess 96a in the operating member and move the trigger to close the valve. |
