GB2452573A

GB2452573A - Door closer having a spacer to adjust the pre-load of a biasing member

Info

Publication number: GB2452573A
Application number: GB0717618A
Authority: GB
Inventors: Alister Peter Reid
Original assignee: Astra Door Controls Ltd
Current assignee: Astra Door Controls Ltd
Priority date: 2007-09-10
Filing date: 2007-09-10
Publication date: 2009-03-11
Also published as: GB0717618D0

Abstract

A door closer for mounting between a door leaf and a door frame, the door closer comprising: an elongate housing 2 for mounting in one of the door leaf or door frame, a plunger 6 disposed in and movable along the housing 2, a biasing element 4 , which may be a helical compression spring, disposed in the housing 2 and biasing the plunger 6 inwardly of the housing 2, a spacer 11 mounted between an end of the biasing element 4 and an opposing end of the plunger 6, the spacer 11 separating the opposing ends of biasing element 4 and the plunger 6 by a predetermined distance, and a tension member 14 having a first end pivotally connected at a first pivot to the plunger and a second end, and an anchor element assembly 26 to which the second end is pivotally connected at a second pivot, the anchor element assembly comprising a mounting member for mounting in the other of the door leaf or door frame. A kit of parts may be provided which includes a plurality of spacers 11. The plurality of spacers may be of different sizes to apply different pre-loads to the spring 4 to suit different doors. Alternatively the plurality of spacers may be of the same length and multiple spacers can be installed to create a larger pre-load. The kit of parts may also include a plurality of biasing elements of different biasing strengths to accommodate different doors.

Description

DOOR CLOSER

This invention relates to a door closer for urging an opened door towards its closed position relative to a doorframe. This invention also relates a kit of parts for assembling a door closer for mounting between a door leaf and a door frame. This invention also relates a method of assembling a door closer for mounting between a door leaf and a door frame.

More particularly, the invention concerns improvements in a door closer, which is of the kind that usually acts between a door leaf and a doorfraine. 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.

There is a general need for such concealed door closers to have a structure to enable them to be incorporated into a variety of different door constructions having a vanety of different uses. For example, the British Standard BS.EN 1154, and its equivalent European Standard EN 1154, sets a variety of technical criteria required to be met by door closers, concealed or not, as summarised in Table 1.

It may be seen that door closers are required to meet specific performance criteria for any particular "power size", dependent on door leaf width and mass. One particularly demanding performance criterion is the need for the door closer to generate a high closing moment in the movement range just before the door is closing, in particular in the range of o to 4 degrees of opening angle. This is important because it is essential that the door is securely closed fully by the door closer, and can overcome any resistance of the door latch mechanism, in order to be able to function safely as a fire door. For example, Table 1 shows that to meet BS.EN 1154 the closing moment for Power sizes 1, 2 and 3, representing progressively larger and heavier doors, over the range of from 0 to 4 degrees of opening angle must be respectively 9, 13 and 18 Nm.

I

While some exposed door closers that are fitted between the top of the door leaf and the door frame can meet these criteria of BS.EN 1154, there is a need in the art for a concealed door closer that can readily meet these criteria in a cost-effective manner.

Furthermore, it would be desirable if a concealed door closer could be provided that can readily be modified selectively to constitute one of a plurality of power sizes.

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 concealed door closer that can readily be structured or modified to provide the combination of sufficient strength so that the door closer can apply a sufficiently large closing forces at low opening angles, from 0 to up to 4°, and versatility so that the door closer can be used in a variety of different door leaf7door frame/door hinge combinations yet still meeting the respective performance criteria, for example BS.EN 1154, for the respective size and weight of the door leaf.

Accordingly, 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, a spacer mounted between an end of the biasing element and an opposing end of the plunger, the spacer separating the opposing ends of biasing element and the plunger by a predetermined distance, and a tension member having a first end connected to the plunger and a second end connected to an anchor element assembly, the anchor element assembly comprising a mounting member, for mounting in the other of the door leaf or door frame.

The present invention further provides a kit of parts for assembling a door closer for mounting between a door leaf and a door frame, the kits of parts comprising: an elongate housing for mounting in one of the door leaf or door frame, a plunger adapted to be disposed in and movable along the housing, a biasing element adapted to be disposed in the housing and to bias the plunger inwardly of the housing, a tension member having a first end connected to the plunger and a second end connected to an anchor element assembly, the anchor element assembly comprising a mounting member, for mounting in the other of the door leaf or door frame, and at least one spacer adapted to be mounted between an end of the biasing element and an opposing end of the plunger, the spacer thereby separating the opposing ends of biasing element and the plunger by a predetermined distance.

The present invention also provides a method of assembling a door closer for mounting between a door leaf and a door frame, the method including the steps of: (a) providing a kit of parts comprising: (i) an elongate housing for mounting in one of the door leaf or door frame, (ii) a plunger adapted to be disposed in and movable along the housing, (iii) a biasing element adapted to be disposed in the housing and to bias the plunger inwardly of the housing, (iv) a tension member having a first end connected to the plunger and a second end connected to an anchor element assembly, the anchor element assembly comprising a mounting member, for mounting in the other of the door leaf or door frame, and (v) a set of plural spacers, each spacer of the set being adapted to be mounted between an end of the biasing element and an opposing end of the plunger, the respective spacer thereby separating the opposing ends of biasing element and the plunger by a respective predetermined distance; (b) selecting one spacer form the set so as to have a selected spacer width corresponding to a respective predetermined distance; and (c) assembling the selected spacer between an end of the biasing element and an opposing end of the plunger thereby to separate the opposing ends of biasing element and the plunger by the respective predetermined distance.

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 conliguration; 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; Figures 5 (a), (b) and (c) are schematic perspective views of the spacer assembly of the door closer of Figure 1 in three different respective configurations, each associated with a respective power size for the door closer, in accordance with one preferred embodiment; and Figures 6 (a), (b) and (c) are schematic perspective views of the spacer assembly of the door closer of Figure 1 in three different respective configurations, each associated with a respective power size for the door closer, in accordance with an alternative preferred embodiment.

Figures 1 to 6 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, hi 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 from the 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 arid 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 has a threaded adjuster pin 52 for adjusting the operation of the hydraulic damper 50.

The threaded adjuster pm 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 outwardly of an inner stop surface 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. 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 flmctions, and simplifies the assembly operation during manufacture.

Also, by extending the threaded adjuster pm 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.

The helical compression spring 4 is compressed between an inner surface 9 of the mounting plate 8 and an annular radially outwardly directed end flange 7 of the plunger 6.

In accordance with the present invention, an annular spacer 11 surrounding the plunger 6 is provided between the distal end 13 of the helical compression spring 4 and the flange 7.

Therefore, the distal end 13 of the helical compression spring 4 is urged against the spacer 11. The proximal end 15 of the helical compression spring 4 is urged against the mounting plate 8.

The helical compression spring 4 has a particular spring constant that is independent of the degree of compression of the helical compression spring 4. The closing force exerted by the helical compression spring 4 at any given longitudinal position of the plunger 6 within the housing 2 is dependent upon its degree of compression. Accordingly, the width, in a longitudinal direction, of the spacer 11 is a parameter that determines the degree of compression of the helical compression spring 4, most particularly when the helical compression spring 4 is least compressed, which is at or near the closing point of the door closer. Therefore the width of the spacer 11 determines the strength of the closing force of the door closer particularly over the last few degrees of the opening angle (i.e. an opening angle of from 0 to 4 degrees).

In accordance with the invention, the spacer width can be varied. This can be achieved by providing a set of plural spacer units or segments, all of the same width, that can selectively be assembled together to form a final spacer of a desired width, which is the sum of the widths of one or mores spacer units. Such an embodiment is shown in Figures (a), (b) and (c) are schematic perspective views of the spacer assembly of the door closer of Figure 1 in three different respective configurations, each associated with a respective power size for the door closer, in Figure 5 (a) the spacer 110 comprises a single spacer unit 111, and has a spacer width S, for example 10 mm. Such a spacer 110 can be used when the door closer is to constitute a power size 1 door closer. This minimum width of the spacer 110 correspondingly reduces the degree of compression of the helical compression spring 4, most particularly when the helical compression spring 4 is least compressed, which is at or near the closing point of the door closer, and so reduces the strength of the closing force of the door closer particularly over the last few degrees of the opening angle (i.e. an opening angle of from 0 to 4 degrees).

In Figure 5 (b) the spacer 112 comprises a pair of adjacent identical spacer units 113, each of which has a spacer width S. for example 10 mm, so that the total spacer width is 2S, for example 20 mm. Such a wider spacer 112 can be used when the door closer is to constitute a power size 2 door closer. This larger width of the spacer 112 correspondingly increases the degree of compression of the helical compression spring 4, most particularly when the helical compression spring 4 is least compressed, which is at or near the closing point of the door closer, and so increases the strength of the closing force of the door closer particularly over the last few degrees of the opening angle (i.e. an opening angle of from 0 to 4 degrees).

In Figure 5 (c) the spacer 114 comprises a trio of adjacent identical spacer units 115, each of which has a spacer width S, for example 10 mm, so that the total spacer width is 3S, for example 30 mm. Such a still wider spacer 114 can be used when the door closer is to constitute a power size 3 door closer. This yet larger width of the spacer 114 correspondingly further increases the degree of compression of the helical compression spring 4, most particularly when the helical compression spring 4 is least compressed, which is at or near the closing point of the door closer, and so increases the strength of the closing force of the door closer particularly over the last few degrees of the opening angle (i.e. an opening angle of from 0 to 4 degrees).

In an alternative embodiment, as shown in Figures 6 (a), (b) and (c), instead of providing a plurality of spacers of identical width, so that one, two, three, etc. or more identical spacers can be assembled together to provide a desired total spacer width, a plurality of spacers of different width can be provided. Figures 6 (a), (b) and (c) show respectively a power size 1 spacer 120, a power size 2 spacer 122 and a power size 3 spacer 124. In this latter alternative embodiment, in the door closer only a single spacer unit 120, 122 or 124 would be present, having the selected width, which could be, selectively, S, 2S or 3S, for

example.

However, an advantage of the previous embodiment having identical spacer units is that only one type of spacer unit needs to be manufactured and in the assembly of the door closer a selected number of the spacer units is inserted between the helical compression spring and the plunger flange.

The invention will be described in greater detail with reference to the following Examples:

Example 1

A door closer having the construction of the illustrated embodiment was provided. The door closer had a helical compression spring which provided without a spacer, or with selected spacers, the following performance criteria. The door closer were installed and tested on a standard 75mm wide one hour door closer 54mm thick.

Closing force at 4 degrees off closing as per EN1 154 No spacer 12 Newton (Power 1) 10mm spacer 14 Newton (Power 2) 20mm spacer 16 Newton (Power 2) 30mm spacer 17 Newton (Power 2)

Example 2

The same door closer as Example 1 was provided with a stronger helical compression spring, having a stronger compressive force for any degree of compression. The door closer with that stronger spring provided without a spacer, or with selected spacers, met the following performance criteria.

Closing force at 4 degrees off closing as per ENI 154 No spacer 18 Newton (Power 2) lOmmm spacer 19.5 Newton (Power 3) 20mm spacer 21 Newton (Power 3) 30mm spacer 23 Newton (Power 3) Accordingly, it may be seem that by providing plural spacers thicknesses, and optionally in conjunction therewith plural spring strengths, a common concealed door closer can be provided that can selectively be fitted with or without one or more spaces, and a selected spring, to achieve a desired performance meeting the EN 1154 standard.

The same result can be achieved for a range of Power 4 to Power 6 door closers with or without, using different spring strengths. By selecting a series of specific spacer widths and a spring strength, it is possible to provide only one spring and a plurality of spacers in combination that could provide a single basic door closer structure that can encompass all power sizes.

For example, the spacers could have a 5mm increment in the series of progressively increasing spacer widths for a particular springs strength, and there could be more than three, for example four or five, spacer widths in the series to provide a succession of plural power sizes.

The present invention provides a door closer having a basic structure that can readily be modified, by selection of an appropriate spacer width, to achieve a predetermined closing force, and thereby achieve a desired power size. This gives significant advantages in manufacture and cost-effectiveness. To provide a range of different power size concealed door closers, the manufacturer can have a single common basis structure and a range of different spacers, or a plurality of identical spacer units that can be assembled together during manufacture. The assembly steps in manufacturing the different power sizes are very similar, selection of the desired spacers being the only variable. This makes manufacture and assembly of a range of power sizes simple and cost-effective.

CD

Table I __________ _______ _________________________________ __________ __________ 1 2 3 4 I 5 6,1 7.8 ______ closing moment Opening Door closer Door closer Recommended Test door. moment efficiency power size door leaf width mass between between any other between 0° between 00 0° and 40 88° and 92 angle of and 600 and 40 mm max. kg Nm mm. Nm. max. Nm mm. Nm mm. Nm Max. % mm.

1 <750 20 9 <13 3 2 26 50 2 850 40 13 <18 4 3 -36 50 3 950 60 18 -<26 6 4 47 55 4 1100 80 26 <37 9 6 62 60 1250 100 37. <54 12 8 83 65 ts.) 6 1400 120 54 <87 18 11 134 65 7 1600 160 87 <140 29 18 215 65 NOTE 1: The door widths given are for standard installations. In the case of unusually high or heavy doors, windy of draughty conditions, or special installations, a larger power size of door closer may be used.

NOTE 2: The test door masses shown are only related to door clçser pow er sizes for the purpose of the test procedure. They are not intended to indicate maximum values for actual use.

Claims

CLAIMS: 1. 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, a spacer mounted between an end of the biasing element and an opposing end of the plunger, the spacer separating the opposing ends of biasing element and the plunger by a predetermined distance, and a tension member having a first end connected to the plunger and a second end connected to an anchor element assembly, the anchor element assembly comprising a mounting member, for mounting in the other of the door leaf or door frame.
2. A door closer according to claim I, wherein the spacer comprises a set of plural spacer units assembled together to form the spacer of a desired width, which is the sum of the widths of the plural spacer units.
3. A door closer according to claim 2, wherein the plural spacer units each have the same width.
4. A door closer according to any foregoing claim, wherein the biasing element is a helical compression spring.
5. A kit of parts for assembling a door closer for mounting between a door leaf and a door frame, the kits of parts comprising: an elongate housing for mounting in one of the door leaf or door frame, a plunger adapted to be disposed in and movable along the housing, a biasing element adapted to be disposed in the housing and to bias the plunger inwardly of the housing, a tension member having a first end connected to the plunger and a second end connected to an anchor element assembly, the anchor element assembly comprising a mounting member, for mounting in the other of the door leaf or door frame, and at least one spacer adapted to be mounted between an end of the biasing element and an opposing end of the plunger, the spacer thereby separating the opposing ends of biasing element and the plunger by a predetermined distance.
6. A kits of parts according to claim 5, wherein the at least one spacer comprises a set of plural spacer units adapted to be assembled together to form the final spacer of a desired width, which is the sum of the widths of the plural spacer units.
7. A kits of parts according to claim 6, wherein the plural spacer units each have the same width.
8. A kits of parts according to claim 5, wherein the at least one spacer comprises a set of plural spacers each of different width.
9. A kits of parts according to any one of claims 5 to 8, wherein the biasing element is a helical compression spring.
10. A kits of parts according to any one of claims 5 to 9, comprising a plurality of the biasing elements, each of the plurality having a respective different biasing strength.
11. A method of assembling a door closer for mounting between a door leaf and a door frame, the method including the steps of: (a) providing a kit of parts comprising: (i) an elongate housing for mounting in one of the door leaf or door frame, (ii) a plunger adapted to be disposed in and movable along the housing, (iii) a biasing element adapted to be disposed in the housing and to bias the plunger inwardly of the housing, (iv) a tension member having a first end connected to the plunger and a second end connected to an anchor element assembly, the anchor element assembly comprising a mounting member, for mounting in the other of the door leaf or door frame, and (v) a set of plural spacers, each spacer of the set being adapted to be mounted between an end of the biasing element and an opposing end of the plunger, the respective spacer thereby separating the opposing ends of biasing element and the plunger by a respective predetermined distance; (b) selecting one spacer form the set so as to have a selected spacer width corresponding to a respective predetermined distance; and (c) assembling the selected spacer between an end of the biasing element and an opposing end of the plunger thereby to separate the opposing ends of biasing element and the plunger by the respective predetermined distance.
12. A method according to claim 11, wherein the set of plural spacers comprises a set of plural spacer units adapted to be assembled together to form the selected spacer of a desired width, which is the sum of the widths of the plural spacer units.
13. A method according to claim 12 wherein the plural spacer units each have the same width.
14. A method according to claim 11 herein the set of plural spacers comprises a set of plural spacers each of different width.
15. A method according to any one of claims 11 to 14, wherein the biasing element is a helical compression spring.
16. A method according to any one of claims 11 to 15, comprising, in step (a), providing a set of a plurality of the biasing elements, each of the plurality having a respective different biasing strength, and further comprising the step, between steps (a) and (c), of (b') selecting one biasing element form the set so as to have a selected biasmg strength.