DOOR CLOSER

This invention relates to a door closing device for urging an opened door towards its closed position relative to a doorframe.

More particularly, the invention concerns improvements in a door closer, which is of the kind that usually acts between a door leaf and a doorframe. This type of door closer typically comprises a housing, a plunger movable along the housing, a biasing element disposed in the housing and biasing the plunger inwardly of the housing, and a tension member having one end connected to the plunger and another end, which extends to an anchor element. The housing is normally installed in a bore in the door leaf and the anchor element installed in the doorframe. However, the positions of the housing and the anchor element may be reversed. The biasing element comprises a spring, which operates to bias the plunger, and consequently the tension member, inwardly of the housing, for closing the door. The tension member comprises an articulated element so that the tension member can be bent around the opening angle of the door relative to the door frame.

Door closers of this kind typically employ as the tension member a conventional elongated chain formed of connecting links. However, the use of such conventional elongated chains has considerable drawbacks when used in door closers of the type described above.

The rotation of adjacent links in conventional elongated chains about a given pivot axis is largely unrestricted. This gives rise to several disadvantages when such chains are used in door closers.

For example, a conventional chain when working in concealed door closers, known in the art, suffers from excessive loss of force transmission because free articulation of the chain link results in frictional losses consequent to the side load imparted on the chain and door closer. Consequently, when such a chain is articulated (as required by door closers of the type described above) the chain is unable to transmit effectively a force throughout its chain length.

Typically, doors are mounted to a door leaf by a projecting hinge. When doors are required to be opened by large angles (for example, where doors are folded back on themselves by opening at an angle of greater than 100°, as much as 120° or even 180°), such hinges project from the door by typically two or more centimetres. In such cases, known door closers are unable to close doors which have been opened by large angles (for

example greater than 100°, up to 120° or even 180°), because they are unable to impart a sufficient force around such angles.

Furthermore, the unrestricted rotation of adjacent chain links can lead to such chains folding back upon themselves. This may happen, for example, when the door is forced shut, and may result in the chain "locking out" or becoming self-entangled.

A further disadvantage of employing such conventional chains arises from energy loss and structural damage due to friction between such chains and the housing/other surfaces.

The Inventor's earlier WO-A-2004/044361 and WO- A-2005/124079 addressed these problems of conventional door chains, and provided a door closer chain comprising a plurality of link elements mutually connected together, each link element having two opposing ends, mutually spaced hi the direction of the length of the chain, each end having a shoulder portion, each shoulder portion being inclined relative to a transverse direction of the chain, and adjacent link elements having opposed shoulder portions which are adapted to abut when the adjacent link elements of the chain are bent around a particular arc or radius.

Although that prior door closer chain provided the advantage that a door closer comprising such a chain can effectively urge an open door towards its closed position even when the door is opened by large angles, for example 120° or even up to 180°, so that the door closers can be used with doors that employ projecting hinges which enable doors to be opened by large angles, the force applied to the chain in such circumstances is so large that there is a possibility of failure of the chain. That chain is difficult to engineer cost- effectively to achieve a sufficiently high tensile strength to be able to transmit very high closing forces, required to close a door leaf by an angle of greater than 100°, as much as 120° or even 180°, without binding of the chain during a rapid closing movement.

It is also known from US-A-1,962,291 to provide a non-jamming chain for door closers and checks of the "piston rod coiled spring" type. However, the chain disclosed in US-A- 1,962,291 still suffers from the problem that the chain is unable to transmit a high closing force throughout its length. Moreover, there is no disclosure of a door closer which is able to be utilised at large closing angles, because the structure of the chain prevents the chain from bending beyond a relatively low angle curved position.

US-A-5,015,022 discloses a chain lock for a sliding door. The chain bends in only one direction. The chain may be latched to form an incompressible column. The chain

disclosed in US-A-5,015,022 also suffers from the problem that the chain is unable to transrm ^' 1^a-high-closmg-force_throughout-its_lengthJbr operation of a hinged door at large closing angles.

Instead of a chain, it is also known to use as a tension member an articulated rigid arm. Such an arm is disclosed in GB-A- 1263666. The arm is pivotally linked at one end to the anchor element and at the other end to the plunger that is biased by a compression spring within the housing. The arm is generally straight but includes an elbow located a short distance from the pivot connection to the plunger. This elbow assists the arm being received in the housing when the door is closed, but permitting the door leaf to open about an operating angle that is only up to about 100° (as shown by the drawing showing the door closer in its fully open configuration). The anchor element comprises a flat plate rebated into the door frame and an outwardly extending gently curved support that holds the pivot connection to the arm. The curvature of the support assists the support also being received in the housing when the door is closed, but permitting the door leaf to open about an operating angle that is only up to about 100°.

The door closer disclosed in GB-A-1263666 suffers from two technical problems. First, the door closer has a structure that does not permit the door leaf to open about an operating angle that is significantly greater than about 100°, e.g. up to about 120°, with a sufficiently strong door closing force at such a large angle. Second, the door closer has a structure with a fixed tension element that that only permits the door leaf to open about a given operating radius relative to the axis of the door hinges. This means that for different door leaf/door frame/door hinge combinations, which result in varying operating radii for the tension element, different door closer structures need to be provided.

GB-A-2044840, GB-A-2415227, GB-A-2167121, GB-A-1497220, US-A-1957308, GB- A-350140, GB-A-1044911 and GB-A-2216181 relate to various door closer constructions.

GB-A-2193281, GB-A-1236827 and US-A-4348141 do not relate to door closers but instead respectively relate to an anchoring bolt, to a method of making a bolt and a bolt made by the method, and to a hollow externally threaded fastener having increased ductility.

The present invention at least partially aims to overcome the problems of the known door closers described hereinabove.

In particular, the present invention aims to provide a door closer that has the combination of increased strength so that the door closer can apply large closing forces at high opening angles, even up to 120°, and versatility so that the door closer can be used in a variety of different door leaf/door frame/door hinge combinations.

Accordingly, in one aspect the present invention provides a door closer for mounting between a door leaf and a door frame, the door closer comprising: an elongate housing for mounting in one of the door leaf or door frame, a plunger disposed in and movable along the housing, a biasing element disposed in the housing and biasing the plunger inwardly of the housing, and a rigid tension member having a first end pivotally connected at a first pivot to the plunger and a second end, and an anchor element assembly to which the second end is pivotally connected at a second pivot, the first and second pivots having parallel pivot axes, the anchor element assembly comprising a mounting member, for mounting in the other of the door leaf or door frame, and a link member extending from the mounting member, the second pivot being located at a free end of the link member remote from the mounting member, wherein the rigid tension member comprises a central portion between the first and second ends thereof, at least a part of the central portion having a reduced thickness relative to the first and second ends in a direction orthogonal to the axes of the first and second pivots.

The present invention further provides a kit of parts for fitting a door closer, the kit comprising a door closer according to the invention in combination with a fitting tool, the fitting tool comprise a U-shaped body with two parallel legs extending away from a base and with a central elongate linear slot, open at one end, between the two legs, and the rigid tension member is received in the slot to retain the rigid tension member partly out of the housing.

In another aspect the present invention provides a door closer for mounting between a door leaf and a door frame, the door closer comprising: an elongate housing for mounting in one of the door leaf or door frame, a plunger disposed in and movable along the housing, a biasing element disposed in the housing and biasing the plunger inwardly of the housing, and a tension member having a first end pivotally connected at a first pivot to the plunger and a second end, an anchor element assembly to which the second end is pivotally connected at a second pivot, and a hydraulic damper for damping the movement of the plunger within the housing, the hydraulic damper including a threaded adjuster pin for adjusting the operation of the hydraulic damper, the threaded adjuster pin being

mounted in the plunger adjacent the first pivot and having an elongate head extending away from the plunger and adjacent to the tension member.

In a further aspect the present invention provides a door closer for mounting between a door leaf and a door frame, the door closer comprising: an elongate housing for mounting in one of the door leaf or door frame, a plunger disposed in and movable along the housing, a biasing element disposed in the housing and biasing the plunger inwardly of the housing, and a tension member having a first end pivotally connected at a first pivot to the plunger and a second end, an anchor element assembly to which the second end is pivotally connected at a second pivot, and a hydraulic damper for damping the movement of the plunger within the housing, the hydraulic damper including a threaded adjuster pin for adjusting the operation of the hydraulic damper, the threaded adjuster pin being captive in the plunger to restrict longitudinal movement of the threaded adjuster pin in the plunger, preferably captive by the first pivot.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a partly cut-away perspective side view of a door closer according to an embodiment of the present invention in a closed configuration;

Figure 2 is a partly cut-away perspective side view of the door closer of Figure 1 in an open configuration;

Figure 3 is a schematic perspective view of the assembly of the link member to the plunger head by the rigid tension member of the door closer of Figure 1;

Figure 4 is a sectional view through the plunger head, rigid tension member and hydraulic adjuster pin of the door closer of Figure 1;

Figure 5 shows a top view of the door closer of Figure 1 prior to installation between a door leaf and a door frame, the door closer being in combination with a fitting tool for retaining the mounting plates of the door closer a desired angular relationship in a partly open condition; and

Figures 6 and 7 show, respectively, plan and side views of the fitting tool shown in Figure 5.

Figures 1 to 4 show a door closer according to the present invention that can be used for urging an opened door towards its closed position relative to a door frame;

An elongate housing 2 in the form of a cylindrical tube comprises a biasing element 4 (shown in phantom) in the form of a helical compression spring. In Figures 1 and 2, for clarity of illustration only the opposed ends of the helical compression spring 4 are shown and the central portion is not shown. A plunger 6 is disposed in and movable along the housing 2. The plunger 6 is biased inwardly of the housing 2 by the biasing element 4. The helical compression spring 4 annularly surrounds the plunger 6. The housing 2 has a mounting plate 8 affixed thereto, the mounting plate 8 having holes 10 extending therethrough for receiving fixing screws. In use, the housing 2 is received in an elongate horizontal cavity in a door leaf (not shown), and the mounting plate 8 is rebated into the edge of the door leaf and affixed thereto, for example by screws.

A rigid tension member 14 has a first end 16 pivotally connected at a first pivot 18 to a plunger head 17 of the plunger 6 and a second end 20 pivotally connected at a second pivot 22 to an anchor element assembly 24. The first pivot 18 has a knurled outer cylindrical surface 19 securely fitting into a cylindrical hole 21 in the plunger head 17, the knurling preventing inadvertent removal of the first pivot 18. The anchor element assembly 24 comprises a mounting member 26, in the form of a plate, for mounting in a door frame (not shown) and an elongate link member 30 extending fromihe mounting member 26. The mounting member 26 is typically rebated into the edge of the door frame and affixed thereto, for example by screws. The second pivot 22 is located at a free end 32 of the link member 30 remote from the plate member 26. The first and second pivots 18, 22 have parallel axes 19, 23.

Conceivably, the mounting positions of the housing 2 and the anchor element assembly 24 may be reversed, with the housing 2 received in the door frame and the anchor element assembly 24 mounted to the door leaf.

A hole 34 in the mounting plate 8 permits movement therethrough of the rigid tension member 14 and the link member 30.

The rigid tension member 14 comprises a linearly straight body 36 that has a central portion 37 between the first and second ends 16, 20. At least a part of the central portion

37 has a reduced thickness relative to the first and second ends 16, 20 in a direction orthogonal to the axes 19, 23 of the first and second pivots 18, 22. In particular, the central portion 37 includes an elongate recess 38 extending longitudinally along a side surface 40 thereof that is a radially inner surface of the rigid tension member 14 during a door opening/closing operation of the door closer 2. The recess 38 has a depth that is greater than 50% of the thickness of the first and second ends 16, 20. The recess 38 has a length that is greater than 50% of the distance between the first and second pivots 18, 22. The recess 38 has a linearly straight bottom surface 39 located between opposed first and second arcuate ends 41, 43. The recess 38 is located longitudinally nearer to the first pivot 18 than to the second pivot 22.

In accordance with the preferred embodiment of the invention, the link member 30 extends from the mounting member 26 at an angle of up to 20 degrees, preferably from 5 to 15 degrees, typically about 10 degrees. The second pivot 22 is a first distance x (in one embodiment about 21 mm) from the mounting member 26 and the first and second pivots 18, 22 are spaced apart by a second distance y (in that one embodiment about 56 mm). Typically, the ratio of the second distance y to the first distance x is from 5:1 to 1:1, more typically from 3:1 to 2:1, yet more typically about 2.5:1.

Typically, the door closer of the invention also incorporates a damper (not shown) to provide a decelerated or damped closing action. Such dampers, for example hydraulic cylinder/piston dampers are well known in the art. If such a damper is present that is adjustable, as disclosed for example in WO-A-2005/124079, the hole 34 permits insertion therethrough of a screwdriver or other tool to adjust the damper.

In the illustrated embodiment a hydraulic cylinder/piston damper 50 for damping the movement of the plunger 6 within the housing 2, having the general structure as disclosed for example in WO-A-2005/124079, is provided. The hydraulic cylinder/piston damper 50 has a threaded adjuster pin 52 for adjusting the operation of the hydraulic damper 50. The threaded adjuster pin 52 is mounted in the plunger head 17 of the plunger 6 adjacent the first pivot 18 and has an elongate head 54 which extends away from the plunger 6 and lies adjacent to the rigid tension member 14. The extending part of the threaded adjuster pin 52 may extend more than 40%, even more than 50%, along the length of the rigid tension member 14. At the other end of the threaded adjuster pin 52 a needle valve member 55 is provided which is employed to adjust the flow of hydraulic fluid in the damper 50. The threaded adjuster pin 52 is captive in the plunger 6 by the first pivot 18, and is prevented from moving beyond respective defined positions in both longitudinal directions. An end 56 of the first pivot 18 is disposed between respective outer and inner

stop surfaces 58, 59 of the threaded adjuster pin 52. The threaded adjuster pin 52 is surrounded by an 0-ring 51 between the needle valve member 54 and the inner stop surface 59 which hydraulically seals hydraulic fluid within the damper 50.

By providing a captive threaded adjuster pin 52, caused by engagement between end 56 and the inner stop surface 59, inadvertent complete removal of the pin by the user is prevented. This would cause loss of hydraulic fluid from the damper 50, and failure of the device. In addition, the captive threaded adjuster pin 52 is prevented from being screwed excessively inwardly, by engagement between end 56 and the outer stop surface 58, which would cause otherwise cause damage to the O-ring 51 surrounding the threaded adjuster pin 52, by squashing the O-ring 51. The use of the first pivot 18 to capture the threaded adjuster pin 52 in the plunger 6 reduces component costs, because the first pivot 18 performs two functions, and simplifies the assembly operation during manufacture.

Also, by extending the threaded adjuster pin 52 by means of the provision of the elongate head 54 which extends away from the plunger 6 and lies adjacent to the rigid tension member 14, the user can employ a screwdriver to rotate the threaded adjuster pin 52 to adjust the damper 50 operation without having to open the door to its fullest extent against the closing bias of the door closer. Even when the door is only partly open, when there is a reduced closing bias from the door closer, the end of the elongate head 54 is exposed at the hole 34 permitting adjustment by the user. This is a significant practical advantage to the user, particularly when the user is frail.

Most preferably, the end of the elongate head 54 is exposed when the door is opened to approximately 90 degrees. This reduces or prevents unauthorised tampering with the threaded adjuster pin 52. A requirement of the European Standard EN 1154 on door closers states that "Control regulators shall either be concealed or operable only by way of a tool". The preferred embodiments clearly meet this stipulation of the standard.

The closed door position is shown in Figure 1. The mounting plate 8 and the plate member 26 abut. The rigid tension member 14 is wholly received in the housing 2, and the link member 30 is also received in the housing 2. The helical compression spring 4 has urged the plunger 6 to its most inward position with respect to the housing 2.

When the door leaf is opened relative to the door frame about the axis of one or more door hinges (not shown), the plunger 6, being attached to the door frame, is pulled in a direction outwardly of the housing 2. Accordingly, the helical compression spring 4 is progressively compressed, as a result of a compression force acting thereon by the plunger

6, and exerts an inward biasing force acting against the opening pulling force on the door leaf. The open position is shown in Figure 2. The mounting plate 8 is spaced from the plate member 26. The link member 30 is pulled out of the housing 2 and the rigid tension member 14 is partly received in the housing 2. The rigid tension member 14 is rotated relative to the plunger 6 about the first pivot 18. The link member 30 is rotated relative to the rigid tension member 14 about the second pivot 22.

In the fully open position, in which the door leaf has been opened by an angle of up to 120°, the rigid tension member 14 is pulled completely out of the housing 2 and the first pivot 18 and the associated end of the plunger 6 are disposed at the hole 34. The rigid tension member 14 has been rotated relative to the plunger 6 about the first pivot 18 so as to lie, in the fully open position, at an angle of up to about 120° relative to the longitudinal axis of the door closer 2. The link member 30 has been rotated relative to the rigid tension member 14 about the second pivot 22.

To achieve the fully open position, the rigid tension member 14 has been rotated towards a side edge 42 of the hole 34. By providing the concave recess 38 on the radially inner surface 40 of the rigid tension member 14, during the door opening/closing operation of the door closer 2 the side edge 42 is received in the concave recess 38 so as to avoid any contact between the rigid tension member 14 and the housing 2 or the mounting plate 8 that would inhibit the door opening/closing operation. Even when the rigid tension member 14 is at an angle of up to 120° relative to the longitudinal axis of the door closer 2, so that the rigid tension member 14 acutely inclined to the mounting plate 8, the side edge 42 is received in the concave recess 38 without contact therebetween. This concave recess 38 therefore enables a much larger opening angle to be achieved, while using a rigid tension member 14, in the form of a linearly straight body, which can transmit a large closing force to the door leaf even when the door leaf is fully opened to an angle of up to 120°.

By providing that the link member 30 extends towards the rigid tension member 14 at an angle inclined to the orthogonal to the plane of the door frame, this provides that the link member 30 can still readily pass through the hole 34 and be accommodated within the housing 2 when the door leaf is closed, but the selected angle causes the link member 30 to be inclined towards the final open orientation of the rigid tension member 14, reducing the angle therebetween in the final open configuration. This in turn reduces the total angular movement of the rigid tension member 14, and permits a higher opening angle to be achieved for a given shape and geometry of the rigid tension member 14 and of the hole

34. This also permits a high closing force to be achieved at the opening angle of up to 120°.

After the door leaf is released, the biasing force of the helical compression spring 4 acts to bias the rigid tension member 14 inwardly of the housing 2, for closing the door. If a damper is present, as in the illustrated embodiment, a reduced damping arrangement may be provided at the end of the closing operation so as to provide an enhanced closing velocity for overcoming any latch resistance so that the door is securely latched when closed.

FIG. 5 shows a top view of the door closer prior to installation between a door leaf and a door frame, the door closer being in combination with a fitting tool for retaining the tension member partly out of the housing, and in particular to permit the mounting plates of the door closer to be oriented at a desired angular relationship in a partly open condition during installation. FIGS. 6 and 7 show, respectively, plan and side views of the fitting tool shown in FIG. 5.

The fitting tool 150 comprises a U-shaped body 152 with two parallel legs 154, 156 extending away from a base 158 and with a central elongate linear slot 160, open at one end 162, between the two legs 154, 156. The body 152 comprises a rigid plate member having opposite parallel end faces 158, 164 which are orthogonal to the through-direction of the slot 160.

In use, the tension member 14 is received in the slot 160 to retain the tension member 14 partly out of the housing 2, and in particular to permit the mounting plate 8 and the mounting member 26 of the door closer to be oriented at a desired angular relationship in a partly open condition during installation. The second end 20 of the tension member 14 includes an enlarged portion 127 that is larger in height (i.e. a direction substantially parallel to the pivot axis of the second pivot 22) than the adjacent central portion 37 of the tension member 14. The enlarged portion 127 thereby provides (see also Figure 3) a pair of upper and lower abutment surfaces 131, 133 of the tension member 14 facing rearwardly, i.e. back into the housing 2 and, when outside the housing 2, back towards the mounting plate 8.

The pair of upper and lower abutment surfaces 131, 133 of the tension member 14 is biased by the spring 4 in the housing 2 against the respective legs 154, 156 of the fitting tool 150. The securing of the fitting tool 150 between the mounting plate 8 and the enlarged portion 127 prevents the entire tension member 14 and the elongate link member 30 pivotally attached thereto from being pulled by the spring bias into the housing 2. The exposed part of the enlarged portion 127 and the elongate link member 30 are of sufficient length to permit sufficient angular separation between the mounting plate 8 and the door frame mounting member 26 to enable them readily to be fitted to the door leaf and the door frame respectively, for example using screws as discussed earlier. After such fitting, the fitting tool 150 is removed by horizontal sliding away (in the direction of arrow A in Figure 5) from the tension member 14, permitting the door to be fully closed under the action of the installed door closer.