GB2415463A - Spring and piston door closer having dual speed closing - Google Patents

Abstract

A door closer comprising a housing defining a volume, a piston 14a for driving connection to a door and movable in the chamber, a separation element 16 movable within the chamber, the separation element dividing the volume into a first chamber 18 and a second chamber 19, a first biasing element 23 acting between the separation element and the piston to urge the piston towards a biased position, a second biasing element 24 acting between the separation element and the housing to urge the piston towards the biased position, a passage 26 to provide fluid communication between the first chamber and the second chamber, and a valve 34 operable to close the passage to prevent provide fluid communication between the first chamber and the second chamber, wherein the separation element is movable to a hold position wherein, when the valve is operated to close the passage, the separation element is held in the hold position such that second biasing element does not act on the piston. Opening valve 34 then allows the second, stronger biasing element to control door closing speed and force of operation.

Description

Title: Door Closer

Description of Invention

This invention relates to door closers.

One such typical door closer comprises a piston having a rack and where the rack meshes with a pinion, and a spring. The pinion is drivingly connected to a door. The piston moves in a volume filled with hydraulic fluid, such as oil, and a passage through a damping mechanism allows fluid to flow from one side of the piston to the other. The piston is resiliently biased by the spring to keep the door closed. Opening the door moves the piston against the spring force acting on the piston, compressing the spring. When the door is released the spring expands, moving the piston to its former position and closing the door.

The closing movement of the door is controlled by the flow of fluid through the damping mechanism in response to movement of the piston. Various types of pistons, racks, springs and damping mechanism are known for this use.

Fire door regulations require that a door closer can generate a sufficient force to close the door against latch resistance and any resistance to closing caused by air pressure or draught. To generate a strong force for mechanical door closers, it is known to provide an appropriate strong spring. However, to meet accessibility requirements for, for example, the elderly or disabled, it is desirable that the door closer generate a relatively low force in response to and opposing the door being opened. While it may be possible to reconcile both these requirements with electrical or hydraulically controlled actuators, such systems may be complex to install and maintain. However, in mechanically operated door closers, the energy stored in the mechanical door closer to provide the door closing force is dependent on the force required to open the door.

An aim of the present invention is to reduce or overcome the above problem.

According to the present invention we provide a door closer comprising a housing defining a volume a piston for driving connection to a door and movable in the chamber, a separation element movable within the volume, the separation element dividing the volume into a first chamber and a second chamber, a first biasing element acting between the separation element and the piston to urge the piston towards a biased position, a second biasing element acting between the separation element and the housing to urge the piston towards the biased position, and a holding element wherein the separation element is movable to a hold position and where the hold element is operable to hold the separation element in the hold position such that when the separation element is held in the hold position the second biasing element does not act on the piston.

The door closer may comprise a passage to provide fluid communication between the first chamber and the second chamber, and where the holding element may comprise a valve operable to close the passage to prevent provide fluid communication between the first chamber and the second chamber, When the door closer is held in the hold position, the valve may be operable to open the passage to permit the separation element to move Tom the hold position.

The separation element may be moved towards the hold position by movement of the piston.

A part of the passage may be defined by an elongate hollow rod which extends longitudinally in the housing and passes through the separation element.

The rod may be provided with an aperture part way along its length to permit fluid flow between the first chamber and second chamber.

The first and second biasing elements may be arranged coaxially around the rod, wherein the separation element has a sliding seal around the rod.

The separation element may have a generally annular outer part and an inner part longitudinally offset from the outer part and connected thereto by a longitudinal wall, wherein one of the first biasing element and the second biasing element engages the outer part and the other of the first biasing element and the second biasing element engages the inner part.

The first resilient biasing element may be disposed in the first chamber and the second resilient biasing element may be disposed in the second 1 0 chamber.

The separation element may be provided with a one-way valve connecting the first chamber and second chamber to allow the separation element to move towards the hold position.

The one-way valve may be operable to permit fluid flow from the second chamber to the first chamber.

The piston may comprise a piston element, a slider which may be longitudinally movable in the volume and a rotary member for connection to a door, whereby rotational movement of the rotary member causes longitudinal movement of the slider.

The first biasing element may extend between the separation element and the slider.

The slider may comprise an abutment part which may be engageable with the separation element.

The door closer may comprise a damper to damp movement of the piston towards the biased position.

The damper may comprise a damping passage to provide fluid communication between opposite sides of the piston element, and a flow restrictor to restrict flow of fluid through the damping passage.

The valve is a solenoid valve.

The volume may be filled with oil.

The resilient biasing elements may comprise springs.

The first resilient biasing element may be weaker than the second resilient biasing element.

According to a second aspect of the invention, we provide a door assembly comprising a door and a door closer.

An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings, wherein; Figure 1, is a schematic diagram of a door closer embodying the present invention, in a first position, Figure 2, shows the door closer of Figure I is a second position, and Figure 3, shows the door closer of Figure 1 is a third position.

Referring now to Figure 1, a door closer is shown generally at 10. The door closer 10 comprises a housing 11 which defines a volume 12. Each end of the housing is closed, by a damping end formation lla and a valve end formation 1 lb which will be discussed in more detail below. In use the volume 12 is filled with a fluid, preferably a incompressible liquid such as oil.

A piston 14 is provided to allow for driving connection to the door. In this example, the piston 14 comprises a piston element 51 and a slider 15_ which is longitudinally slidable within the volume 12 and a rotary member 15b which is drivingly connectable to, and rotatable with, a door (not shown). The slider 15_ and rotary member 15_ are provided with intermeshing teeth, such that rotation of the rotary member 15b in ananti clockwise direction as shown in Figure 1 causes movement of the slider 15a through the volume to the right as shown in Figure 1.

A separation element is located within the volume shown at 16. The separation element 16 is moveable longitudinally within the volume 12, and is provided with a seal 17 to provide a sliding, fluid-tight seal between the separation element and the inner face of the housing 11. The separation element 16 thus divides the volume into a first chamber 18 and a second chamber 19. The separation element 16 comprises a generally annular part 20 on which the seal 17 is provided and an end part 21 which is connected to the outer part 20 by a longitudinally extending wall 22. A first bias element 23 extends between the end part 21 of the separation element 20 and an abutment part 14_ of the piston 14. In the present example, the first bias element 23 comprises a resilient biasing element and particularly a helical spring. The first bias element 23 acts to urge the piston 14 in a direction to the left as shown in Figure 1, towards a bias position as shown in Figure 1.

A second bias element 24 is provided, extending between the separation element 16 and a part of the housing 11, in this example the valve end formation 11_. In this example, the second bias element 24 engages the right hand face of the annular part 20 and is thus located radially outwardly of the first bias element 23. In this example, the second bias element 24 again comprises a resilient biasing element, and in particular a helical spring. The second bias element 24 is stronger, that is provides a greater force, than the first bias element 23. The first bias element 23 is located in the first chamber 18 and the second bias element 24 is located in the second chamber 19.

To provide fluid communication between the first chamber 18 and the second chamber 19, a fluid passage is provided generally indicated at 26. The fluid passage is provided in part by a hollow rod 28 which extends longitudinally of the volume 12 and passes through the end part 21 of the separation element 16. The end part 21 is provided with a seal 29 to provide a sliding seal between the separation element and the hollow rod 28. The end of the hollow rod 28 nearest the formation 1 lb is in communication with an end chamber 30 which itself is in flow communication with the second chamber 19 through an end passage 32. The formation 11_ further comprises a holding element, in this example a valve assembly, generally shown at 34, which is operable to close the fluid connection between the chamber 30 and the passage 32 and hence prevent fluid flow between the first chamber 18 and second chamber 19. In this example, the valve assembly 34 comprises a solenoid valve having a coil shown at 36 and an armature 38 moveable in response with to supply of electrical current to the coil 36. The armature 38 has an end part which engages a valve seat 42 to prevent flow communication between the end chamber 30 and end passage 32.

To further allow for the passage of fluid between the first chamber 18 and the second chamber 19, the hollow rod is provided with an aperture 44 part way along its length. The end part 21 of the separation element 16 is also provided with a one way valve, generally shown at 46, in this example comprising a ball 47 which may engage a valve seat 48 to prevent passage of fluid through the one way valve 46 and move away from the valve seat 48 to allow passage of fluid through the one way valve 46. In the present example, the ball 47 comprises a resilient material such as a nitrite and the valve seat 48 is a suitable metal, such that the ball 47 deforms slightly to engage the seat and provide a fluid-tight seal.

The damping end formation 1 la comprises a damping assembly generally shown at 50. The damping assembly 50 interacts with the piston element 51 of the piston 14 which provides a sliding seal with the inner walls of the housing 11. A hollow tube 52 extends through the piston element 51 and has an outlet 53 shown generally to the left of the piston element 51 in Figure 1.

An adjuster 54 is operable to limit the size of the outlet 53 to control the rate of which fluid can pass through the hollow tube 52 from one side of the piston element 51 to the other. The piston element 51 has a central part 56 extending to the left of the piston element 51 as seen in Figure 1 which extends over the outlet 53 when the slider 15_ is at or near its bias position as shown in Figure 1.

When the door closer 10 is in the configuration shown in Figure 1, it will be clear that, when the door is opened causing rotation of the rotary member 15_ and the rightward movement of the slider l Sa, the slider l Sa will act on the separation element 16 and urge it to the right against the resistance of the relatively strong second bias element 24. There will also be some biasing force leftwards as a result of the compression of the first bias element 23. The S second bias element 24 is sufficiently strong to provide the desired closing force appropriate for closure of the door in response to a fire, for example as required by relevant building or fire rules or regulations. As discussed above, this force may be excessively high for use in normal circumstances, in particular a door to be opened by elderly, infirm or disabled users. To overcome the problem, the separation element 16 may be moved to a hold position as described below, where the force acting on the slider 1 S_ to urge it towards its bias position is supplied by the first bias element 23 alone, which preferably meets the desired accessibility requirements.

To move the separation element to its hold position, as shown in Figure IS 2 the door is opened sufficiently to rotate the rotary element IS_ to urge the slider lSa to the right as shown in the Figure. As the separation element 16 moves to the right, fluid is displaced out of the second chamber 19, into the first chamber 18. Fluid passes through the one way valve 46, and also in the fluid passage 26, through the aperture 44 and into the hollow rod 28 so that it flows into the second chamber 18 to an outlet 36 at the end of the hollow rod 28, and, if the valve assembly 34 has been operated to withdraw the end part 40 from the valve seat 42, through the passage 32 and through the hollow rod 28. As the end part 21 of the separation element 16 passes the aperture 44, fluid flow from the second chamber 19 to the first chamber 18 will only be possible through the one way valve 46 and via the passage 32 providing the valve 34 is open. If the valve 34 is then closed, or is maintained closed throughout opening the door, and the door is then released, the separation element 16 will attempt to move to the left in the volume 12 as shown in Figure 2. The pressure of fluid in the first chamber 18 and second chamber 19 will however act to close the one way valve 46, thus preventing all fluid flow between the first chamber 18 and second chamber 19 and hence preventing the separation element 16 from moving leftwards. The only biasing force acting to return the piston 14 to its leftwards bias position therefore will come from the relatively weak first bias element 23 as illustrated in Figure 3. Thus, whilst the separation element is in its hold position as shown in Figures 2 and 3 the door is opened against the resistance of the relatively weak first bias element 23 and closed by the force generated by the relatively weak bias element 23.

The damper operates to slow the movement of the door towards the end part of its movement. As the piston element 51 moves leftwards, fluid is displaced from the left hand side of the separation element within the volume 12 piston, passes through the hollow tube 52 and passes to the right hand side of the piston element 51 in the volume 12. As the piston element 51 approaches its leftmost position, the projecting part 56 will gradually obstruct the outlet 53, restricting the rate at which fluid can flow from one side of the piston element 51 to the other and thus slowing movement of the piston 14 towards the end of its travel. This will thus, for example, prevent a door banging into a door frame at too high a speed, with resulting noise and damage.

When the door closer 10 is in the configuration of Figure 3 and thus the separation element 16 is in its hold position, it will be apparent that the separation element 16 may be released from the hold position by operating the valve assembly 34. If the valve assembly 34 is operated to connect the chamber 36 and passage 32, and hence open the fluid connection 26 between the first chamber 18 and second chamber 19, the separation element 16 will be free to move to the left under the course of the second bias element 24. Movement of the separation element 16 to the left will bring it into contact with the abutment part 14a of the slider 15a and act to urge it towards its biased, closed position with a higher closing force than that provided by the first bias element 23, thus providing the required closing force appropriate in the event of a fire.

Ideally, the valve apparatus 34 is operated in a fail-safe manner, such that the valve is held in its closed position when electrical power is supplied to the coil 36 on electrical connection 39, and in the event of loss of power on the connection 39, for example through a fault or in response to a fire alarm, the valve apparatus 34 moves to an open position whether by virtue of a biasing element in the valve or as a response to fluid pressure within the volume 12, to release the separation element 16 from its hold position. It will be apparent that when the valve apparatus 34 is open, the door closer 10 operates as a conventional door closer.

Thus, when a door is first installed, or after a fire alarm or test, or when it is otherwise necessary due to arm the door, i.e. move the separation element 16 to its hold position, it is only necessary to ensure that the valve apparatus 34 is in its closed position and then open the door sufficiently to move the separation element 16 sufficiently far such that the end part 21 passes beyond the aperture 44. No further adjustment or control are required. It will be apparent that the aperture 44 may be located where desired along the hollow tube 28 to provide the appropriate hold position for the separation element 16.

It will be apparent that at least one of the aperture 44 and the one way valve 46 might be omitted and that arming of the door could be achieved by opening the door to a desired extent when the valve assembly 34 is in its open position and then closing the valve assembly 34, but this requires more control on the part of the user and may not provide an appropriate desired setting.

It will be clear that when providing the separation element in such a way that the first and second bias elements 23, 24 extend concentrically, the overall length of the housing 11 can be reduced. It will also be apparent that any other valve apparatus and damper may be provided as desired.

Advantageously, the piston 14, damping mechanism 50 and housing 11 may be of conventional type, and adapted in accordance with the present invention by providing the separation element 16, hollow rod 28 and valve assembly 34.

In the present specification "comprise" means "includes or consists of" and "comprising" means "including or consisting of".

The features disclosed in the foregoing description, or the following claims, or 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.

Claims (24)

1. A door closer comprising a housing defining a volume a piston for driving connection to a door and movable in the chamber, a separation element movable within the volume, the separation element dividing the volume into a first chamber and a second chamber, a first biasing element acting between the separation element and the piston to urge the piston towards a biased position, a second biasing element acting between the separation element and the housing to urge the piston towards the biased position, and a holding element, wherein the separation element is movable to a hold position and where the holding element is operable to hold the separation element such that, when the separation element is held in the hold position, the second biasing element does not act on the piston.

2. A door closer according to claim 1 comprising a passage to provide fluid communication between the first chamber and the second chamber, and where the holding element comprises a valve operable to close the passage to prevent provide fluid communication between the first chamber and the second chamber.

3. A door closer according to claim 2 wherein, when the separation element is held in the hold position, the valve is operable to open the passage to permit the separation element to move from the hold position.

4. A door closer according to claim 3 wherein the separation element may be moved towards the hold position by movement of the piston.

5. A door closer according to any one of claims 2 to 4 wherein a part of passage is deemed by an elongate hollow rod which extends longitudinally in the housing and passes through the separation element.

6. A door closer according to claim 5 wherein the rod is provided with an aperture part way along its length to permit fluid flow between the first chamber and second chamber.

7. A damper according to Claim 5 or Claim 6 in which the first and second biasing elements are arranged coaxially around the rod, wherein the separation element has a sliding seal around the rod.

8. A door closer according to any one of the preceding claims wherein the separation element may be moved towards the hold position by movement of the piston.

9. A door closer according to any one of the preceding claims wherein the first resilient biasing element is disposed in the first chamber and the second resilient biasing element is disposed in the second chamber.

10. A door closer according to any one of the preceding claims wherein the separation element is provided with a one-way valve connecting the first chamber and second chamber to allow the separation element to move towards the hold position.

11. A door closer according to claim 10, wherein the one-way valve is operable to permit fluid flow from the second chamber to the first chamber.

12. A door closer according to any one of the preceding claims wherein the piston comprises a piston element, a slider which is longitudinally moveable in the volume and a rotary member for connection to a door, whereby rotational movement of the rotary member causes longitudinal movement of the slider.

13. A door closer according to claim 12 wherein the first biasing element extends between the separation element and the slider.

14. A door closer according to claim 12 or claim 13 wherein the slider comprises an abutment part which is engageable with the separation element.

15. A door closer according to any one of the preceding claims comprising a damper to damp movement of the piston towards the biased position.

16. A door closer according to claim 15 where dependent directly or indirectly on claim 12 wherein the damper comprises a damping passage to provide fluid communication between opposite sides of the piston element, and a flow restrictor to restrict flow of fluid through the damping passage.

17. A door closer according any one of the preceding claims in which the valve is a solenoid valve.

18. A door closer according to any one of the preceding claims wherein the volume is filled with oil.

19. A door closer according to any preceding claim in which the resilient biasing elements comprise springs.

20. A door closer according to any preceding claim in which the first resilient biasing element is weaker than the second resilient biasing element.

21. A door closer substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

22. A door assembly comprising a door and a door closer according to any one of the preceding claims.

23. A door assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

24. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.