GB2284856A

GB2284856A - Spring actuated door closer

Info

Publication number: GB2284856A
Application number: GB9422531A
Authority: GB
Inventors: Frederick Hugh Place
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-11-16
Filing date: 1994-11-08
Publication date: 1995-06-21
Anticipated expiration: 2014-11-08
Also published as: GB2284856B; GB9422531D0

Abstract

A spring actuated door closer 1 comprises a compression spring assembly 2 and a tension spring assembly 3 incorporating a lost motion mechanism 21, 22, 23. The compression spring assembly 2 is connected to a door frame 16 with one end of the tension spring assembly 3 being connected to a hinged door 15 and the other end being pivotally connected to the door frame 16 and to the compression spring assembly 2. The arrangement is such that initial rotation of the tension spring assembly 3 as the door 15 is opened to a pre-determined position causes compression of a compression spring 6 with no extension of a tension spring 18 and further rotation causes extension of the tension spring 18 so that when the door 15 is released the tension spring 18 urges the door towards the closed position and the compression spring 6 subsequently unloads to urge the door 15 shut overcoming any latching resistance. The door closer may replace all or part of the doorstop in the head of the door frame. <IMAGE>

Description

DOOR CLOSER ASSEMBLY Door closers are widely used and especially with fire doors. A conventional arrangement may comprise a simple spring which is loaded as the door opens and subsequently urges the door towards a closed position when the door is released. However, control of closing speed and latching is generally poor with this arrangement: either the returning force of the spring is sufficient to close the door at a suitable closing speed but is incapable of overcoming the resistance of the door latch or, alternatively, the returning force of the spring is such that the door closes quickly and slams shut. In the latter case the resistance of the spring tends to make opening the door difficult.

More elaborate door closers exist which include a hydraulic damper and which include separate door closing and latching mechanisms. These closers tend to be expensive, bulky, suffer from fluid oil leaks, require expert regular attention and are generally considered to be an eyesore.

According to a first aspect of the present invention, a door closer system is arranged to replace all or part of a door stop in the head of a door frame and comprises a door closer assembly at least partially enclosed within a housing which has a cross-section corresponding to that of a standard door stop.

Preferably, the cross-section of the door closer assembly housing is rectangular in configuration and of a size substantially 25 x 44 mm.

The door closer assembly of the present invention is designed to replace part or all of a door stop which extends across the head of a door frame and its mechanism is concealed when the door is closed. The door closer assembly mechanism is fixed to a side of the door which lies adjacent to the door stop in the door frame head and so entirely conceals the door closer system from both sides of the door when the door is closed. Where the cross sectional area of a particular door stop is substantially the same as the door closer assembly housing, any exposed surfaces of the housing may be painted to match the door frame and so disguise the whole door closer assembly as part of the door stop.

According to a second aspect of the present invention, a door closer assembly comprises a first spring assembly, a second spring assembly mechanically linked to the first spring assembly and arranged to move with the door, wherein the first spring assembly provides a latching force as the door approaches a closed position but provides substantially no effective closing force when the door is in an open position and the second spring assembly provides an initial closing force when the door is in the open position and includes a lost motion mechanism which ensures the second spring assembly provides no further closing force after the door has been partly closed.

Preferably, the door closer assembly includes damping means to control the closing speed of the door as the second spring assembly unloads and the door returns towards the closed position.

The first spring assembly and second spring assembly may comprise any conventional type of spring, including gas springs, but preferably the first spring assembly comprises a compression spring and the second spring assembly comprises a tension spring.

Preferably, the tension spring assembly comprises a tension spring fixed within and at one end of a first tube.

The one end of the first tube is pivotally connected to a bracket fixed to the hinged door at a point distanced from the door hinge. The first tube is housed within a second tube and is capable of sliding within the second tube. The second tube is pivotally connected at one end to the door frame so that, in use, as the door is opened the first tube is capable of sliding partially outwards from within the second tube as the first and second tubes each pivot with the door.

Preferably, the one end of the first tube includes a tension spring adjuster assembly.

Preferably, the lost motion mechanism comprises a length of rod fixed to the one end of the second tube and which terminates at a point within the first tube between the two ends of the tension spring. In use, as the door opens and the first tube slides outwardly from the second tube, the free end of the tension spring is moved towards the free end of the rod and subsequently when the door reaches the pre-determined open position, the tension spring and rod engage so that further outward movement of the first tube causes the tension spring to extend.

Preferably, the free end of the rod includes a stop tube to allow the free end of the rod to engage the end of the tension spring once the tension spring has travelled a pre-determined distance with the first tube.

The damping means may be provided by forming the first spring as a gas spring but, preferably, the damping means forming part of the tension spring assembly comprises a friction washer associated with a pressure screw which can be adjusted to control the closing speed of the door leaf.

The tension spring assembly pivots about the pressure screw as the door is opened and closed.

Preferably, the compression spring assembly comprises a compression spring fixed at one end to the door frame and at the other end is pivotally connected to the other end of the tension spring assembly.

Preferably, the compression spring is attached to the pivotal connection by a rod.

Preferably, the compression spring assembly includes a compression spring adjuster assembly forming a connection between the rod and compression spring for adjusting the degree of pre-compression of the compression spring in its most relaxed state. More preferably, the compression rod of the compression spring assembly may be connected to the bracket at any one of a plurality of pivot points to adjust the latching action.

Preferably, the door closer assembly is partially enclosed within a housing comprising a cover plate and a base plate wherein the housing may be fixed to the door frame head and adjacent door stop to conceal the door closer assembly when the door is closed.

The preferred embodiment of the present invention operates in the following manner.

As the door is opened, the tension spring assembly pivots with the door causing the first tube to slide outwards from the second tube which is pivotally attached to the door frame head and urges the compression spring assembly rod toward the compression spring thus compressing the compression spring. At an opening position determined by the length of the lost motion mechanism rod, the free end of the tension spring is engaged by the stop tube so that further opening of the door causes the tension spring to extend.

Further rotation of the door causes the compression spring to flex without substantially any further compression whilst allowing the tension spring to continue to extend.

When the door is released, the tension spring assembly unloads and causes the door to close at a pre-determined closing speed until the pre-determined opening position is reached and the tension spring is fully unloaded. Thereafter the friction reduces the closing speed and the compression spring unloads to urge the door shut.

The arrangement of two springs in the present invention gives rise to a door closer assembly in which there are three adjustable actions: a closing action, at a closing speed determined mainly by the unloading of the tension spring assembly as the door closes from, say, a 1250 opening angle to a 500 opening angle; by this time the closing action is taken over by the compression spring the action of which is opposed by the damping action of the friction washer which prevents the door being urged to close too quickly in spite of the substantial force exerted by the compression spring; and, a latching action in which compression spring assembly urges the door closed against any additional resistance of the latch; the additional latch resistance slowing down the door movement and thereby dissipating the damping action of the friction washer so that the full force of the compression spring is available to overcome the additional resistance of the latch.

An additional advantage of the present invention is that the door closer assembly is extremely robust and compact and is of such a size that it can replace part of or all of an existing door stop to conceal the assembly so that it is not visible when the door is shut. The assembly can also simply be fitted directly under an existing door stop or door frame head without interfering with the door frame itself.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows a sectional plan view of a door closer assembly; Figure 2 shows a sectional side elevation of a compression spring assembly; Figure 3 shows a sectional side elevation of a tension spring assembly; Figure 4 shows a sectional end elevation of the door closer assembly of Figure 1 taken along the line A - A and along the line G Figure 5 shows a sectional end elevation of the door closer assembly of Figure 1 taken along the line B - B; Figure 6 shows a sectional end elevation of the door closer assembly of Figure 1 taken along the line C - C; Figure 7 shows a sectional end elevation of the door closer assembly of Figure 1 taken along the line D - D;; Figure 8 shows a sectional end elevation of the door closer assembly of Figure 1 taken along the line E - E; and, Figure 9 shows a sectional end elevation of the door closer assembly of Figure 1 taken along the line F - F.

Figure 1 of the drawings shows a door closer assembly 1 comprising a compression spring assembly 2 and a tension spring assembly 3.

The compression spring assembly 2 is fixed to a door frame 4 via a bracket 5 and comprises a compression spring 6, a compression rod 7 and a compression spring adjuster assembly 8. The compression rod 7 is connected via a pivot 9 to a bracket 10 at any of the pivot points 91 to 96 which forms part of the tension spring assembly 3 to control the latching action.

The tension spring assembly 3 comprises a first square tube 11 housed within a second square tube 12. The first tube 11 is pivotally connected via a pin 13 to a bracket 14 fixed to the door leaf 15. A stop member 27 is provided to prevent the pivot pin 13 of the tension spring assembly 3 from disengaging the bracket 14 fixed to the door 15 as the door 15 opens and closes. The bracket 10 connecting the compression spring assembly and tension spring assembly is fixed to one side of the second tube 12.

Referring to Figure 2, the compression spring adjuster assembly 8 comprises a threaded nut and washer arrangement to allow for fine adjustment of the pre-loading of the compression spring.

Referring to Figure 3, the tension spring assembly further comprises a tension spring 18, a tension spring adjuster screw 19 at one end of the first tube 11, a friction washer 20 and a pressure screw 17 at the other end of the first tube 11, and a rod 21 fixed at one end of the second tube 12 and passing into the first tube 11 and terminating at a point between the two ends of the tension spring 18. The free end of the rod 21 includes a thickened stop tube 22 which is adapted to be capable of engaging a ring 23 forming part of the free end of the tension spring 18.

The assembly further comprises a cover plate 24 and a base plate 25 which are fixed to the door frame head 16 and door stop 26. The base plate 25 receives the pressure screw 17 of the tension spring assembly 3 to pivotally connect the second tube 12 of the tension spring assembly to the door frame head 16.

In use, when the door 15 is opened the tension spring assembly 3 rotates about pressure screw 17 and pivot 13 with the door 15 causing the pivot 9 connecting the compression rod 7 to the bracket 10 to follow a circular locus about the pivot axis of the pressure screw 17. This action initially causes the compression spring 6 to compress. Meanwhile, the first tube 11 slides outwardly from the second tube 12 causing the entire tension spring 18 to move relative to the fixed rod 21 and stop tube 22.

Once the door reaches a certain opening angle of say 50 , the ring 23 of the free end of the tension spring 18 engages the stop tube 22 of the rod 21 so that further outward movement of the door 15 causes the tension spring 18 to extend. The precise opening angle at which this occurs is determined by the length of the rod 21 and the position of the stop tube 22. Hence the rod 21 and stop tube 22 constitute the lost motion mechanism of the present invention.

As the door opening angle exceeds 900, the compression spring 6 undergoes very little further compression and instead flexes outwardly.

When the door 15 is released, the tension spring assembly 3 unloads and urges the door 15 towards the closed position about the pressure screw 17 at a closing speed which is dependent upon the energy stored in the tension spring 18. As the door closes the first tube 11 is pulled back to within the second tube 12 and the tension spring 18 relaxes. At the pre-determined opening position the stop tube 22 and ring 23 of the tension spring 18 disengage so that the tension spring 18 no longer has an effect on the closing of the door. Meanwhile, pivotal movement of the tension spring assembly about the pressure screw 17 and friction washer 20 tends to dampen the closing speed of the door 15.

As the door 15 approaches the closed position the effect of the compression spring assembly 2 is at a maximum and delivers the final impulse required to urge the door shut.

As is shown in the Figures, the door closer assembly 1 is enclosed on all but one side by the cover plate 24 and base plate 25. Where the door stop 26 around the door frame head 16 is wider and deeper than the cover plate 24, the entire assembly 1 may replace part or all of the door stop 26 to lie adjacent to the door frame head 16 so that the assembly 1 is not visible when the door 15 is closed.

Even if the door stop 26 is not wide enough to allow complete concealment of the assembly 1, only the cover plate 24 will be visible when the door is closed and this may be painted to match the door frame and disguise the assembly as part of the door stop. However, if preferred, the assembly 1 can simply be mounted directly under the existing door stop 26, thus avoiding the need to interfere with the door frame structure as required in the refurbishment of existing door sets.

Claims

1. A door closer assembly comprising a first spring assembly, a second spring assembly mechanically linked to the first spring assembly and arranged to move with the door, wherein the first spring assembly provides a latching force as the door approaches a closed position but provides substantially no effective closing force when the door is in an open position and the second spring assembly provides an initial closing force when the door is in the open position and includes a lost motion mechanism which ensures the second spring assembly provides no further closing force after the door has been partly closed.

2. A door closer assembly according to claim 1, further comprising damping means to control the closing speed of the door as the second spring assembly unloads and the door returns towards the closed position.

3. A door closer assembly according to claim 1 or 2, wherein the first spring assembly comprises a compression spring and the second spring assembly comprises a tension spring.

4. A door closer assembly according to any preceding claim, wherein the door closer assembly comprises a compression spring assembly which is capable of being secured to a door frame, a tension spring assembly which includes a lost motion mechanism and which is capable of being secured to a hinged door at one point and connected to the door frame at another point so that it is moveable with the door, and wherein the compression spring assembly is pivotally connected to the tension spring assembly and is arranged so that, in use, initial rotation of the tension spring assembly about a pivot as the door is opened to a pre-determined open position causes compression of the compression spring with no extension of the tension spring and further rotation causes extension of the tension spring so that when the door is released the tension spring is effective to return the door towards a closed position and the compression spring subsequently unloads to urge the door shut and overcome any latching resistance.

5. A door closer assembly according to claim 3 or 4, in which the tension spring assembly comprises a tension spring fixed within and at one end of a first tube and the one end of the first tube is pivotally connected to a bracket fixed to the hinged door at a point distanced from the door hinge, wherein the first tube is housed within a second tube and is capable of sliding within the second tube and the second tube is pivotally connected at one end to the door frame so that, in usee as the door is opened the first tube is capable of sliding partially outwards from within the second tube as the first and second tubes each pivot with the door.

6. A door closer assembly according to claim 5, wherein the one end of the first tube includes a tension spring adjuster assembly.

7. A door closer assembly according to claim 5 or 6, wherein the lost motion mechanism comprises a length of rod fixed to the one end of the second tube and which has a free end which terminates at a point within the first tube between the two ends of the tension spring so that, in use, as the door opens and the first tube slides outwardly from the second tube, the free end of the tension spring is moved towards the free end of the rod and subsequently when the door reaches the pre-determined open position, the tension spring and rod engage so that further outward movement of the first tube causes the tension spring to extend.

8. A door closer assembly according to claim 7, wherein the free end of the rod includes a stop tube to allow the free end of the rod to engage the end of the tension spring once the tension spring has travelled a pre-determined distance with the first tube.

9. A door closer assembly according to any one of claims 4 to 8, wherein the compression spring assembly comprises a compression spring fixed at one end to the door frame and at the other end is pivotally connected to the other end of the tension spring assembly.

10. A door closer assembly according to claim 9, wherein the compression spring is attached to the pivotal connection by a rod.

11. A door closer assembly according to claim 10, wherein the compression spring assembly includes a compression spring adjuster assembly forming a connection between the rod and compression spring for adjusting the degree of precompress ion of the compression spring in its most relaxed state.

12. A door closer assembly according to any preceding claim, wherein the door closer assembly is partially enclosed within a housing comprising a cover plate and a base plate wherein the housing may be fixed to the door frame head and adjacent door stop to conceal the door closer assembly when the door is closed.

13. A door closer system for replacing all or part of a door stop in the head of a door frame comprising a door closer assembly at least partially enclosed within a housing which has a cross-section corresponding to that of a standard door stop.

14. A door closer system according to claim 13, wherein the cross-section of the door closer assembly housing is rectangular in configuration and of a size substantially 25 x 44 mm.

15. A door closer assembly substantially as shown in and described with respect to Figures 1 to 9 of the drawings.