GB2456508A

GB2456508A - Door closer having an electrically operated valve holding means to prevent a return bias from being applied to a door

Info

Publication number: GB2456508A
Application number: GB0800607A
Authority: GB
Inventors: Roger Henry Jeynes; Mark John Stonelake
Original assignee: Samuel Heath and Sons PLC
Current assignee: Samuel Heath and Sons PLC
Priority date: 2008-01-15
Filing date: 2008-01-15
Publication date: 2009-07-22
Anticipated expiration: 2028-01-15
Also published as: GB0800607D0; GB2456508B; HK1128508A1

Abstract

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.

Description

2456508

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Title: Door Closer

5 Description of Invention

This invention relates to a door closer and more particularly to a door closer of the kind including an actuator assembly intended for concealed fitting within the thickness of a door, and an anchor member for fixing to a door frame, and in 10 which an operating member is coupled to the anchor member and is movable within the actuator assembly under the action of a driving apparatus, usually including one or more mechanical springs, and under the control of a damper mechanism to regulate the rate of movement of the door in the direction of closure without significantly restricting the rate of movement of the door in the 15 direction of opening.

Such a door closer is disclosed in our previous UK patent no 2415014 in which there is a resilient thrust device including a pair of leaf springs which act generally perpendicularly to the direction of movement of the operating 20 member to apply increased driving force to the operating member over a final part of the door movement into its closed position.

It is known to provide a door with a holding mechanism device to retain the door in an open position against the force exerted by a door closer tending to 25 drive the door to its closed condition. To comply with fire regulations, it is a demand that the holding mechanism device releases the door for closing by the door closer in the event that for example, a fire alarm is actuated.

According to a first aspect of the invention we provide a door closer including an 30 anchor assembly for mounting on a door frame, an actuator assembly for mounting within the thickness of a door to move with the door between open and closed positions relative to the door frame, and a holding mechanism, the

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actuator assembly including an operating member coupled by a link to the anchor assembly and mounted for a range of movements between a fully retracted position when the door is closed and the holding mechanism is inoperative, in which the anchor assembly is held adjacent to the actuator 5 assembly and an extended position in which the anchor assembly is in spaced relation to the actuator assembly, a resilient driving apparatus arranged to exert a driving force on the operating member so that when the holding mechanism is inoperative, in use, the operating member is driven towards the retracted position to draw the anchor assembly and the actuator assembly together to move the 10 door towards its closed position relative to the frame, and the actuator assembly further including a damper mechanism operatively connected to the operating member so as to damp movement of the operating member at least as it is driven in a direction towards the fully retracted position as the door is closed by the driving apparatus, the damping mechanism being fluid operated and 15 including a cylinder containing fluid, a piston rod carrying a piston which divides the cylinder into first and second chambers, and a passage for fluid to flow at least from the first chamber to the second chamber in response to the operating member being driven towards the fully retracted position when the holding mechanism is inoperative, and the holding mechanism including a valve which is 20 moveable to a closed condition when the door is opened to prevent the flow of fluid through the passage from the first to the second chamber to prevent the operating member being driven towards the fully retracted position, and the holding mechanism including an electrically operated retaining device to retain the valve in the closed condition.

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Thus the present invention enables a door fitted with the door closer, to be opened against the force of the resilient driving apparatus from the closed to an open or partially open condition, and the holding mechanism, by preventing the operating member being driven back towards the fully retracted position, permits 30 free swinging of the door i.e. the door will remain in the open or a partially open condition to which the door is opened against the force of the resilient driving

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mechanism, until the holding mechanism is released, and may be freely swung between the closed condition and the open condition to which the door was opened against the force of the resilient driving mechanism. If desired the door may be opened further against the force of the resilient driving mechanism and 5 may then be freely swung between the closed condition and the further opened condition, with the holding mechanism retaining the operating member in the position to which is it moved as the door is opened or further opened.

The closer may include a biasing device to move the valve member to an open 10 condition when the electrically activated retaining device is de-activated.

The biasing device may act upon a trigger member which is moved to close the valve when the electrically activated retaining device is operated and the door is opened, the electrically activated retaining device including an electromagnet 15 and retaining the trigger member against the force of the biasing device until the electromagnet is de-activated, upon which occurrence, the biasing device acts to open the valve. Thus the door will be closed by the resilient driving apparatus driving the operating member.

20 In use, the electrically activated retaining device may be operated by an external electrical supply, for example which may be discontinued when a fire alarm of a building in which the door is installed, is operated.

Preferably the door closer damping mechanism includes a second passage for 25 fluid from the second to the first chamber as the operating member moves in response to the door being opened, in substantially unimpeded manner. For example, the second passage may include a one way valve to prevent the fluid passing from the first to the second chamber.

30 The door closer may include a resilient thrust device arranged to exert an increased driving force on the operating member over a defined part of its range

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of movement as the operating member approaches the fully retracted position, corresponding to movement of the door over a final part of its movement into its closed position, and wherein the resilient thrust device includes at least one leaf spring which acts in a direction transverse to the direction of movement of the 5 operating member, to apply the increased driving force to the operating member, the spring carrying a roller which when the door is closed, is received in a recess and from which recess the roller moves as the door is opened, the trigger member cooperating with the roller as the roller is moved from the recess, to move the trigger member against the force of the biasing device to close the 10 valve.

As the door is continued to be opened, and the trigger member is retained by the electrically operated retaining device, the trigger member may ride over the roller so that the roller may continue to move relative to the trigger member.

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The recess may be provided in an external surface of a body which moves with the operating member, and when the thrust device is operative, the leaf spring exerts a force generally radially towards an axis along which the body moves as the door is closed by the driving apparatus.

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Embodiments of the invention will now be described with reference to the accompanying drawings in which:-

FIGURE 1 is side view of a door cioser in accordance with the present invention, 25 exclusing a housing, and showing positions of components when the door is partially open;

FIGURE 2 a sectional side view of one embodiment of the door closer of figure 1, showing the positions of the components of the door closer when the door is 30 both closed (in the upper part of the figure) and in the open condition (in the lower part of the figure);

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FIGURE 3 is an alternative side cross sectional view of part only of the door closer of figure 1 again showing components of the door closer when the door is both closed (in the upper part of the figure) and in the open condition (in the 5 lower part of the figure);

FIGURE 4 is an enlarged underside plan sectional view of a holding mechanism of the door closer of figures 1 to 3 showing more detail;

10 FIGURE 5 is side sectional view corresponding to the view of figure 4.

The door closer as illustrated in the figures includes an anchor assembly 10 which is in use, mounted in or on an edge a door frame facing an edge of a door hinged to the frame, and an actuator assembly 30 which is mounted in use, 15 within the thickness of the door.

The anchor assembly 10 includes a mounting plate 11 which is fixed relative to the frame, and an adjustable anchor member 12 which is this example is a plate which is spaced from the mounting plate 11 on the side thereof remote from the 20 door, by an adjustable distance. An adjusting screw 13 is engaged in a threaded hole 14 formed in the anchor member 12, rotation of the screw 13 varying the spacing of the anchor member 12 and mounting plate 11 for the purpose hereinafter described.

25 The mounting plate 11 is also formed with a pair of apertures 17 near the ends thereof and the anchor member 12 is formed with a pair of apertures 18 aligned with the apertures 17. The anchor member 12 is coupled to the one ends of a pair of articulated linkages 20 e.g. by transverse pins 21 which are accommodated within the thickness of the anchor member 12, and the other 30 ends of the linkages 20 are each coupled to a cross member 35 of an operating member 22 of the actuator assembly 30 for a purpose hereinafter described.

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The actuator assembly 30 is so dimensioned as to be suitable for fitting within the thickness of the door and for this purpose is provided with a housing 23 (shown only in figure 2) which includes an edge mounting member 24 which in 5 use is located at the edge of the door, the edge mounting member 24 having apertures 25 which align with the apertures 17 of the anchor assembly mounting plate 11, and outwardly extending flange parts 26 which have apertures to receive fixing screws 27 for fixing the actuator assembly 30 to the door.

10 Within the housing 23 of the actuator assembly 30 there is provided a rod 31 which has a threaded end portion fixed to the edge mounting member 24, a central axis A of the rod 31 coinciding in this example, with an axis of symmetry of the actuator assembly 30.

15 The operating member 22 includes a pair of parallel shafts 32 which each extend generally parallel to the rod 31, the parallel shafts 32, each being coupled to a respective articulated linkage 20 so that articulation is permitted between the linkage 20 sections, and the shafts 32 as the door is opened and closed. The articualted linkages may be provided by a plurality of articualted links i.e. lionks

20 which are pivoted to one another, or alternatively other links may be provided, for example, cables or chains.

The operating member 22 further includes, at the other ends of the shafts 32, the cross member 35 which aiso carries a body 38 which receives within it, the rod

25 31, and the cross member 35 further includes an aperture 37 though which the rod 31 extends, as the operating member 22 and hence the body 38 earned thereby, moves in the housing 23 in the direction of the axis A, as the door is opened and closed.

30 The operating member 22 is biased inwardly of the housing 23 towards a retracted or "door closed" position shown in the upper part of figure 1, under the

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force of a resilient driving apparatus provided by a pair of driving springs 45. The springs 45 extend between the cross member 35 and the edge mounting member 24 and are each received on a respective floating sleeve 40 received on a shaft 32 of the operating member 22. In the illustrated embodiment, the 5 driving springs 45 are each provided by a pair of coil springs which may be oppositely wound and separated by a flange 41 of the respective floating sleeve 40, so that as the resilient force applied to the operating member 22 to retract the articulated linkages 20, is normalised over the entire range of movement of the operating member 22.

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The driving springs 45 when compressed, act on the cross member 35 to drive the latter inwardly of the actuator assembly 30 (i.e. to the right as seen in figure 1) to the retracted position and to draw the shafts 32 and the associated linkages 20 inwardly of the housing 23 so as to bring the mounting plate 11 of the anchor 15 assembly 10 up to the edge mounting member 24 of the actuator assembly 30, thereby urging the door to its fully closed position.

When the door is opened, as shown in the lower part of figure 1, the shafts 32 and cross member 35 of the operating member 22 are drawn outwardly (i.e. to 20 the left), thereby causing the driving springs 45 to be compressed further. When the door is released from its "door open" position, when a holding mechanism 110 to be described below is inoperative to retain the operating member 22, the driving springs 45 act to return the cross member 35 and the shafts 32 to their starting positions, thereby bringing the door back to its closed position relative to 25 the frame.

The actuator assembly 30 further includes a damper mechanism 50 to regulate the rate of closure of the door under the action of the driving springs 45.

30 The damper mechanism 50 as seen best in figure 3 includes a fixed piston 51 formed on the rod 31 at a position intermediate its ends, and a cylinder 52

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provided in the body 38 carried by the operating member 22. The cylinder 52 contains a fluid, preferably hydraulic fluid.

The cylinder 52 has at the end closest the cross member 35, a seal 53 which is 5 moveable along the rod 31 with the cylinder 52 and contains the fluid in a second, inner chamber 65 of the cylinder 52 between the seal 53 and the piston 51. At the other end of the cylinder 52, there is a further seal 54 which is moveable along the rod 31 with the cylinder 52 and contains the fluid in a first, outer chamber 66 of the cylinder 52 between the seal 54 and the piston 51.

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The piston 51 is annular and includes a seal 58 which provides a seal between the piston 51, and each of the cylinder 52 and the rod 31, as the cylinder 52 moves along the rod 31. The piston 51 is fixed to the rod 31 by a pair of pins 57a, 57b. Thus the piston 51 divides the cylinder 52 into inner and outer 15 chambers 65, 66.

A first fluid passage 70 generally parallel to the rod 27 is provided in a wall of the body 38 to enable fluid to pass from the outer chamber 66 to the inner chamber 65 in a controlled manner, as the door is moved to the closed position by the 20 resilient driving apparatus provided by the springs 45. This is shown in the upper part of figure 3. The first fluid passage 70 includes an adjustable throttle 71 which restricts fluid flow along the first fluid passage 70, the throttle 71 being adjustable to adjust the restriction to fluid flow.

25 Fluid flows to the throttle 71 in the first fluid passage 70 from the outer cylinder chamber 66 through a transverse connecting passageway 75. Fluid passes from the first fluid passage 70 to the inner cylinder chamber 56, through passages of the holding mechanism 110 as will be described below, and via a further transverse connecting passageway 76, to provide a required fluid flow restriction 30 and thus controlled fluid flow.

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The throttle 71 is adjustable using a key through an access opening 80 in the edge mounting member 24, from the edge of the door.

A second fluid passage 82 generally parallel to the rod 31 is provided in the wall 5 of the cylinder 52 too, to enable fluid to pass from the inner chamber 65 to the outer chamber 66, as the door is moved to the open position, with such fluid flow being substantially unimpeded.

As can be seen in the lower part of figure 3, the second fluid flow passage 82 10 communicates with each of the inner and outer chambers 65, 66 via respective transverse connecting passages 83, 85, but within the second fluid flow passage 82 there is provided a one way valve 84. In this example this includes a sprung ball valve member 88 which is urged towards a seat 89, such that the valve member 88 prevents fluid flow from the outer to the inner 15 passage 66, 65 as the door is closed, but is lifted off its seat 89 in response to fluid pressure as fluid flows from the inner to the outer chamber 65, 66 as the door is opened.

Thus fluid may flow freely from the inner chamber 65 to the outer chamber 66 via 20 the second fluid flow passage 82 and the door may be opened against the force exerted by the driving apparatus 45. However, in response to movement of the door towards its closed position, fluid flow from the outer to the inner chamber 66, 65 through the first fluid flow passage 70 is permitted in a controlled manner via the throttle 71, when the holding mechanism 110 is inoperative. Any fluid fiow 25 from the inner to the outer chamber 65, 66 via the throttle 71 during door opening is inconsequential.

The door closer further includes a resilient thrust device 90 to exert an increased driving force on the operating member 22 over a defined part of its range of 30 movement as the operating member 22 approaches the retracted position,

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corresponding to movement of the door over a final part of its movement into its closed position.

The thrust device 90 includes a pair of springs, in this example leaf springs 92, 5 which each act in a direction generally normal to the direction of movement of the operating member 22 which moves along axis A. Other spring arrangements which act in this direction could alternatively be provided.

The leaf springs 92 are each fixed at or at least close to their one ends relative to 10 the edge mounting member 24 of the actuator assembly 30, and each carry at or adjacent their opposite ends, a cam follower provided by a roller 94. The leaf springs 92 are mounted to either side of the rod 31, are made of spring steel strip, and are configured to exert a resilient force generally radially perpendicularly inwardly of the rod 31.

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A respective cam 96 is provided on the exterior surface of the body 38, which the cam followers 94 follow during the final part of the door's movement towards its closed position.

20 The shape of the cam 96 will determine a resultant force arising by the generally radially inward force exerted by the leaf springs 92 acting on the cam 96, the cam 96 shape being such that the resultant force acts in a direction generally along the axis of the rod 31 to increase the driving force provided by the driving apparatus provided by the driving springs 45. The cam 96 is designed to enable 25 the maximum increased thrust initially to be applied as the followers 94 follow an initial part of the cams 96 which initial part of the cams 96 may correspond to a door position where a door latch of a spring latching mechanism first engages its keeper as the door closes, and at which position a spring force of the latching mechanism needs to be overcome. In this example, the cam 96 each have a 30 respective recess 96a in which the roller cams 94 sit when the door is in its fully closed condition.

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The position of the body 38 on the rod 31, where the increased driving force becomes operative, i.e. the point at which the resilient thrust device 90 becomes operative to apply the increased driving force to increase the force exerted on 5 the operating member 22 to close the door, over a defined range of the closing movement, may be adjustable by varying the relative positions of the operating member 22 and the anchor member 12 of the anchor assembly 10. This is achieved as previously described by adjusting the position of the anchor member 12 relative to the mounting plate 11 by turning the adjusting screw 13.

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Thus, the effect of the thrust device 90 is to provide an additional closing force during the final stage of a door closing operation, thus overcoming any resistance to door closure which may, for example, be imposed by a latching mechanism which operates between the door and the door frame. The thrust 15 device 90 also maintains an urging force on the operating member 22 to assist in maintaining the door closed.

During door closing, prior to the point at which the cam followers 94 engage the cams 96, the cam followers 94 may ride on a carrier part surface 100 without 20 exerting any increased driving force to the force exerted by the driving apparatus, i.e. the driving springs 45.

Typically, the range of door closing at which the increased driving force is applied, is between 0° and about 7° of opening but may be up to 15° of opening.

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According to the invention, the door closer includes a holding mechanism 110 which has the function of preventing the driving apparatus springs 45 from driving the operating member 22 so as to close the door, until the holding mechanism is released.

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This is achieved by preventing the hydraulic fluid passing from the outer chamber 66 to the inner chamber 65 of the cylinder 52 along the first fluid flow passage 70 by moving a valve V to a closed condition. In the present example, as best seen in figures 4 and 5, the body 38 has secured to it, a valve block 5 111 which includes the valve V. The valve V in this example is a ball valve which is rotatable about a valve axis C indicated in figure 4, as hereinafter explained, between an open condition as shown in figures 4 and 5, when fluid from the first fluid passage 70 can pass through the valve V substantially unimpeded, and a closed condition in which the fluid cannot flow though the 10 valve V. When the valve V is in its open condition, fluid from the first fluid passage 70 in the body 38, may pass through a drilling 114 into an aligned passage 115 of the valve block 111, then through the valve V , and then through another passage 117 of the valve block 111 into a second drilling 118 in the body 38, back to the first fluid passage 70, and hence via the further 15 transverse connecting passageway 76 of the body 38 to the inner cylinder chamber 65.

The fluid is constrained to pass through the valve block 111 by a blockage in the first fluid passage 70 provided in this example by a ball bearing 119 which 20 is held against a seat 120 by a throttle plug 121 which is screwed into position through the connecting member 35 of the operating mechanism 22.

When the valve V is in the open condition, the holding mechanism 110 is inoperative. When the valve V is rotated about the valve axis C so ihat there is 25 no communication for the fluid from the passage 115 to the passage 117 of the valve block 111. Once the door is opened from its fully closed position, and when the holding mechanism 110 is operative, as no fluid flow from the outer chamber 66 of the piston at one side of the piston 51 to the inner chamber 65 is permitted, the operating member 22 will be retained in the position to which 30 it has been moved. The door may be freely swung between the positon to which the door was opened to the fully closed position, but the driving

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apparatus 45 will be inoperative. If it is desired to open the door further than the point to which it was previously opened, this is permitted as fluid flow trough the second fluid passage 82 will remain unaffected, but the operating member 22 will remain in whatever position it is moved to as the door is further 5 opened.

When the holding mechanism 110 is again rendered inoperative by rotating the valve V about the valve axis C to the position shown in figures 4 and 5, fluid may again pass via the throttle 71 and thus in a controlled manner, from 10 the outer 66 to the inner chamber 65, via the valve V, to permit the driving apparatus 45 to act on the operating member 22 to move the operating member 22 to the retracted condition.

The valve V includes a valve spindle 125 which is rotatable about the valve 15 axis C to rotate the valve V. The spindle 125 includes an operating pin 126 which extends transversely to the valve axis C. The operating pin 126 is moveable as a lever, to rotate the valve V in one direction i.e. anticlockwise to the position as seen in figure 1, by a coil spring 130 of the holding mechanism 110, which spring 130 acts between the operating pin 126 and a shoulder 131 20 of the valve block 111. The spring 130 acts on the pin 126 to move the pin 126 so as to urge the valve V to the open position shown in the figures i.e. in which the holding mechanism 110 is inoperative.

The operating pin 126 is moveable ciockwise to move the vaive V to the 25 closed position to render the holding mechanism 110 operative, by a trigger member 136. The trigger member 136 is made of spring steel strip and includes an opening 137 in which the operating pin 126 is received, so that lateral movement of the trigger member 136 i.e. movement parallel to the symmetry axis A, results in turning of the operating pin 126 and hence rotation 30 of the ball valve V about the valve axis C clockwise or anticlockwise depending on the direction of trigger member 136 movement.

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The holding mechanism 110 further includes an electromagnet 138 which acts when electrically activated, to hold the trigger member 136 to retain the pin 126 rotated clockwise against the mechanical force of the coil spring 130 of 5 the holding mechanism 110.

The trigger member 136 extends along the sliding body 38 towards the cam roller 94, where the trigger member 136 terminates in a cam formation 139. As can be seen in figure 2, when the door is fully closed, the holding mechanism 10 110 is inoperative, and the roller cam follower 94 is acting on cam surface 96 to maintain the door fully closed, and the trigger member cam formation 139 is immediately adjacent the roller 94.

As the door is initially opened and the roller cam follower 94 moves along the 15 cam surface 96, the roller 94 will engage the trigger member cam formation 139 to move the trigger member 136 to the right as seen in figures 1 and 2 which has the effect of moving the operating pin 126 clockwise and hence to close the valve V. The trigger member 136 extends through a slot 140 in the cross member 35, and then bends parallel to the cross member 35 to provide 20 an end part 142, between the cross member 35 and the electromagnet 138. When the electromagnet 138 is activated, the end part 142 will be attracted by the electromagnet 138, and then the trigger member 136 will be retained by the electromagnet 138 against the force of the holding mechanism coil spring 130.

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As the door continues to be opened, the cam formation 139 of the trigger member 136 will ride up over the roller cam 94 of the leaf spring 92, so that the cam 94 and cam formation 139 can move relative to one another, e.g. to the position indicated in figure 1.

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As the valve V will now be rotated to, and retained by the electromagnet 138 in the closed condition, the operating member 22 will be prevented from being driven back to the fully retracted condition by the driving apparatus 45 until the electromagnet 138 is deactivated to release the trigger member 36 to be 5 moved by the holding mechanism coil spring 130 so as to turn the operating pin 126 anticlockwise then to open the valve V.

In one example, the electromagnet 138 may normally be activated by an electrical supply to permit of free swinging of the door as previously described. 10 However the electromagnet is de-activated when for example a fire alarm of the building in which the door is installed, is operated, so that the door closer acts to close the door automatically, to provide fire and smoke protection. Alternatively the door closer may be electrically connected to an alternative external signalling device which when operated acts to discontinue the 15 electrical supply to the electromagnet 138 of the door closer to open the valve V and then allow the door to be closed by the resilient driving mechanism 45.

Many modifications may be made without departing from the scope of the invention. For example, in the embodiments described, the operating member 20 22 has been provided by a pair of shafts 42 arranged symmetrically about an axis A, but in another example, only a single shaft and consequently a single driving spring 45 (which may include one or more than one coil spring) and articulated link 20, may be provided.

25 In another example, the valve V need not be a ball valve and may not be provided in a valve block 111 secured to the sliding body 111. For example the valve V may have a valve member which is linearly moveable to open/close the valve V, which linear movement may be achieved so that the holding mechanism 110 functions as described above, possibly without the need to 30 convert the linear movement of a trigger member 136 to a rotational valve movement.

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The valve V may be provided in the first fluid passage 70 rather than in a valve block 111. The trigger member 136 need not act upon the roller cam 94 of the leaf spring 92, which in another example may not be provided at all. However 5 the movement necessary to close the valve V to prevent the controlled fluid flow necessary for the door to be automatically closed, may be triggered by an alternative mechanism.

If desired, any mutually engaging services of the various components could be 10 coated with a material having a low co-efficient of friction (such as PTFE) to reduce wear problems as far as possible and to maximise the increased force applied by the thrust drive.

The features disclosed in the foregoing description, or the following claims, or 15 the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

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Claims

1. A door closer including an anchor assembly for mounting on a door frame, an actuator assembly for mounting within the thickness of a door to move 5 with the door between open and closed positions relative to the door frame, and a holding mechanism, the actuator assembly including an operating member coupled by a link to the anchor assembly and mounted for a range of movements between a fully retracted position when the door is closed and the holding mechanism is inoperative, in which the anchor assembly is held adjacent 10 to the actuator assembly and an extended position in which the anchor assembly is in spaced relation to the actuator assembly, a resilient driving apparatus arranged to exert a driving force on the operating member so that when the holding mechanism is inoperative, in use, the operating member is driven towards the retracted position to draw the anchor assembly and the actuator 15 assembly together to move the door towards its closed position relative to the frame, and the actuator assembly further including a damper mechanism operatively connected to the operating member so as to damp movement of the operating member at least as it is driven in a direction towards the fully retracted position as the door is closed by the driving apparatus, the damping mechanism 20 being fluid operated and including a cylinder containing fluid, a piston rod carrying a piston which divides the cylinder into first and second chambers, and a passage for fluid to flow at least from the first chamber to the second chamber in response to the operating member being driven towards the fully retracted position when the holding mechanism is inoperative, ana the holding mechanism 25 including a valve which is moveable to a closed condition when the door is opened to prevent the flow of fluid through the passage from the first to the second chamber to prevent the operating member being driven towards the fully retracted position, and the holding mechanism including an electrically operated retaining device to retain the valve in the closed condition.

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2. A closer according to claim 1 wherein the closer includes a biasing device to move the valve member to an open condition when the electrically activated retaining device is de-activated.

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3. A colser according to claim 2 wherein the biasing device acts upon a trigger member which is moved to close the valve when the electrically activated retaining device is operated and the door is opened.

4. A closer according to claim 2 or claim 3 wherein the electrically activated 10 retaining device includes an electromagnet which retains the trigger member against the force of the biasing device until the electromagnet is de-activated.

5. A closer according to any one of the preceding claims wherein the electrically activated retaining device is activated by an external electrical supply.

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6. A closer according to any one of the preceding claims wherein the damping mechanism includes a second passage for fluid from the second to the first chamber as the operating member moves in response to the door being opened, in substantially unimpeded manner.

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7. A closer according to claim 6 wherein the second passage includes a one way valve to prevent the fluid passing from the first to the second chamber.

8. A closer according to any one of the preceding ciiams wherein the closer 25 includes 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 fully retracted position, corresponding to movement of the door over a final part of its movement into its closed position.

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9. A closer according to claim 8 wherein the resilient thrust device includes at least one leaf spring which acts in a direction transverse to the direction of

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movement of the operating member, to apply the increased driving force to the operating member, the spring carrying a roller which when the door is closed, is received in a recess and from which recess the roller moves as the door is opened, the trigger member cooperating with the roller as the roller is moved 5 from the recess, to move the trigger member against the force of the biasing device to close the valve.

10. A closer according to claim 9 wherein as the door is continued to be opened, and the trigger member is retained by the electrically operated retaining

10 device, the trigger member rides over the roller so that the roller may continue to move relative to the trigger member.

11. A closer according to claim 9 or claim 10 wherein the recess is provided in an external surface of a body which moves with the operating member, and

15 when the thrust device is operative, the leaf spring exerts a force generally radially towards an axis along which the body moves as the door is closed by the driving apparatus.

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