GB2323409A - Door closer - Google Patents

Abstract

With door opening, door-closer piston 16 moves in direction A, compressing closing spring 17 as fluid flows from chamber 22 via piston chamber 18 to chamber 21. A DC supply applied to coil 40 moves core 39 to close valve 34, 36, preventing fluid flowing from chamber 18 to chamber 22, and holding the door open. Cutting the DC supply, e.g. by a fire alarm, opens valve 34, 36 and spring 17 closes the door. The position of coil 40, biased by spring 52, is adjusted by knurled nut 48, to move the coil along core 39 to adjust the manual force required to overcome the coil and start door closing.

Description

Title: Door Closer Description of Invention The invention relates to a door closer controlling the movement of a door to which it is fitted, and in palticular, to a door closer which can hold the door open or release the door dependant on the status of an electronic valve. These are commonly known as electronic door closers.

Electronic door closers which can hold doors open are well known.

They are used for example, in hotel corridors where fire doors may be held open during the day for the convenience of guests, but may be released automatically if smoke is detected or a fire alarm activated.

Such door closers may be overidden, when holding a door open, by pulling the door closed against the "hold" of the closers. This is known as manual release. Prior art door closers do not provide release adjustment whereby the force required for manual release may be adjusted to what is considered appropriate for the application concerned.

It is an object of the invention to provide an alternative form of electronic door closer which does not suffer from the same disadvantages.

According to the present invention there is provided an electronic door closer comprising: (a) a body defining an internal chamber; (b) a piston within the chamber, defining first and second cavities of variable size to either side of the piston. and a cavity within the piston, (c) fluid filling the cavities; (d) biasing means biasing the piston in one direction; (e) passageways for the flow of fluid between the cavities; and, (f) an electronic valve controlling flow of fluid and when closed holding the piston against the biasing means; wherein the electronic valve comprises adjustment means whereby the force required for manual release of a door held open by the closer may be adjusted.

The present invention provides the advantage that the force required for manual release of a door held by the door closer may be adjusted as appropriate for the application concerned.

Preferably electronic valve comprises a magnetic coil and a core upon which it acts, and adjustment means comprises means for adjusting the relative positions of the coil and core. The adjustment means comprises means for adjusting the position of the coil axially with respect to the core.

Preferably the means for adjusting the position of the coil comprises an external thread around the core, a nut which engages on the external thread, the coil being a sliding fit around the core, and biasing means biasing the coil towards the nut.

Conveniently, the nut is adapted for rotation by hand without the use of tools.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIGURE 1 illustrates an electronic door closer according to the invention in cross section, with oil way drillings shown in removed section for clarity, the closer being in door open position; FIGURE 2 illustrates the electronic door closer of Figure 1 in door closed position; FIGURE 3 illustrates part of the electronic door closer of Figure 1 in greater detail showing the oil flow path during door opening, and, FIGURE 4 shows the same area as Figure 3, with the oil flow path for door closing indicated.

An electronic door closer 10 comprises a body 11 defining a cylindrical chamber 12 therein. The chamber 12 is closed at one end by a plug 13 and at the other end by an end cap 14. The end cap 14 seals to the body 11 means of 0 rings 15.

Within the chamber 12 is a piston 16 which defines a first cavity 21 between itself and the plug 13, and a second cavity 22 between itself and the end cap 14. The piston is biased towards the end of the chamber 12 closed by the plug 13 by a spring 17 within the second cavity 22. The piston 16 has a central cavity 18 which along one wall 19 is provided with rack teeth (not shown). Engaged with the teeth are complimentary teeth (not shown) of a pinion 20 which extends out of the body 11 in the normal manner for connection to an arm or a system of levers attached, in use, either to a door or its frame so that opening and closing movement of the door is accompanied by axial movement of the piston 16 within the cylindrical chamber 12. The movement of the piston 16 alters the respective volume of the first and second cavities 21,22, although their total volume remains the same. Since this arrangement is of conventional form, it will not be described further.

The cylindrical chamber 12 is filled with hydraulic fluid, such as oil, which occupies the first cavity 21, second cavity 22, and piston cavity 18.

A passageway 23 is provided between the first cavity 21 and the piston cavity 18. The passageway 23 contains a check valve 24.

A main passageway 25 connects the piston cavity 18 to the second cavity 22. A bore 26 is provided between the main passageway 25 and piston cavity 18. Two further bores 27,28 are provided between the main passageway 25 and either the piston cavity 18 or the second cavity 22, dependant on the position of the piston 16. A connecting passageway 29 is provided between the main passageway 25 and passageways in the end caps 14 as will now be described.

The connecting passageway 29 communicates with a bore 30 containing a filter 31, which prevents particles entering the passageways in the end cap 14. The bore 30 communicates with a valve chamber 32 which contains a oneway valve 33 comprising a valve member 33a in the form of a rubber ball, and a spring 33b. The valve 33 permits flow from the second cavity 22 to the main passageway 25, but does not permit the reverse flow from the main passageway 25 to the second chamber 22. The valve chamber 32 communicates with a bore 34 leading to a second valve chamber 35. The valve chamber 35 contains a valve member 36, in the form of a ball bearing, which is part of an electronic valve 37, which further comprises a plunger 38, a core 39 and a coil 40. The coil 40 has a 24 volt electlicity supply thereto (not shown) and its operation will be described below. The valve chamber 35 communicates with a further bore 41 which in turn communicates with the second cavity 22.

The door closer 10 further comprises an adjuster screw 42 having a head 43 for engagement with a screwdriver or the like, and at the opposite end a plug portion 44. An 0 ring seal 45 is provided around the head 43. With the adjuster screw 42 positioned as shown in figure 1, the plug portion 44 is engaged in and hence closes off bore 28 from the main passageway 25. When the adjuster screw is screwed outwards the plug portion 44 disengages from and hence opens the bore 28. This adjustment allows for the use of the door closer with different arm configurations as will become clear later. As the bore 28 is significantly narrower than the main passageway 25, the plug portion 44 does not prevent flow of fluid along the main passageway 25 when positioned as shown in figure 1.

The door closer 10 further comprises an adjustment means 46 whereby the force required to release manually a door held open by the closer 10 may be adjusted as appropriate for the application concerned. The adjustment means 46 comprises an extemal thread 47 on the portion of the electronic valve 37 containing the core 39. A nut 48 which is knurled on its external surfaces and thus adapted for rotation by the fingers is internally threaded and engaged on the thread 47. The coil 40 has an end cap 49 attached to its outer end which is a sliding fit around the core 39 and within a recess 50 in the casing 51 of the valve 47. The core 40 is biased outwardly of the casing 51 in an axial direction by a spring 52 but is retained within the casing 51 by means of the nut 48. The exact position of the coil 40 with respect to the core 39 is adjusted by means of rotation of the nut 48, hence adjusting the force required to overcome the closer 10 when in use to hold a door open.

Operation of the door closer 10 will now be described.

When the door is closed, the door closer 10 is positioned as shown in figure 2. The piston 16 is at one end of its travel, towards the plug 13, with the first cavity 21 at its minimum volume and the second cavity 22 at its maximum volume.

As the door is opened, the pinion 20 rotates and drives the piston 16 in the direction of arrow A against the bias of the spring 17. The movement of the piston 16 reduces the volume of the second cavity 22 and forces oil out of the second cavity 22. Initially the flow is via bores 27 or 27 and 28, the main passage 25 and bore 26. But as the piston 16 moves axially along the chamber 12, in the direction of arrow A, the end 16a passes the bores 28 and subsequently 27 such that they are closed off from the second cavity 22. The fluid then opens one-way valve 33, against the bias of spring 33b, passes through bore 30, and through the filter 31, into connecting passage 29, main passageway 25 and bore 26, 27 or 28 into the piston cavity 18. This flow path is illustrated by arrow 50 in Figure 3. As piston cavity 18 is of fixed dimensions, oil also flows through the passageway 23 into the first cavity 21.

When the door is open, the door closer 10 may be in the position shown in figure 1.

If the 24 volt supply is connected to the coil 40 of the electronic valve 37, then the core 39 and plunger 38 are moved to the right as shown in figure 1, holding the valve member 36 in a position such that it closes the bore 34. Thus, flow of oil between the piston and second cavities 18,22, is prevented by the oneway valve 33 and the electronic valve 37, and the door is held in the open position against the bias of spring 17.

If the 24 volt supply to the coil 40 of the electronic valve 37 is cut, for example if a fire alarm is activated, the core 39 and plunger 38 are no longer held towards the right in figure 1, and the valve member 36 is free to move away from the end of the bore 34. Oil can then flow between the cavities and the piston 16 can be moved under the bias of the spring 17 in the direction of arrow B. The movement decreases the volume of the first cavity 21, forcing oil out of that cavity.

The oil flows as follows, as the piston 16 moves in the direction of arrow B, oil from the first cavity 21 passes through the bore 23 into the piston cavity 18, from whence it flows via bores 26,27, and 28 if open, into the main passageway 25, to the connecting passageway 29 through the filter 31 and bore 30, through valve chamber 32, into bore 34, through valve chamber 35 and finally through bore 41 to the second cavity 22. This flow path is illustrated by arrow 51 in figure 4. As the piston 16 moves in direction B, the bore 28 is closed from the piston cavity 18, and subsequently also the bore 27 is closed, each of these bores then being opened to the second cavity 22 as the piston 16 continues to move.

The presence of bores 27 and 28 permits a flow of oil from the second cavity 22 to the piston cavity 18 via bore 27 or 28, the main passageway 25 and the bore 26 during the initial stages of the opening of the door. Similarly, they permit flow of fluid from the piston cavity 18 to the second cavity 22 via the bore 26, the main passageway 25 and bore 27 and 28 if open, during the final stages of the closing the door. These bores prevent the use of the electronic valve to control the door closed, or within in this case 70" of closed, in order to comply with British Standard requirements.The two bores 27 and 28 provide this facility for two different arm configurations, allowing the door closer 10 to be adapted for use with either configuration. This provides a significant advantage over the prior art where the arm configuration must be known at the time of manufacture as different components are used as necessary.

If the door is held open by the closer 10 and a person wishes to release the door manually, they simply pull the door against the force of the door closer 10 and if sufficient force is applied, the electronic valve 37 is overcome and fluid flows as if the door had been released by cutting of the 24 volts applied to the coil 40. The force required to achieve this manual release depends on the exact position of the coil 40 with respect to the core 39. Hence, the force required to release the closer 10 manually is adjusted by rotation of the knurled nut 48 on the external thread 47. This moves the coil 40 inwardly or outwardly with respect to the coil 39 until the desired release force is achieved.

In the accompanying figures, the oilway drillings 25 to 29 are shown in removed section for clarity. However, they are provided within the body 11 of the door closer 10. This provides the advantage that the only seal required for moving parts for the basic operation of the door closer 10 is provided in the end 16a of the piston 16.

The features disclosed in the foregoing description 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, or a class or group of substances or compositions, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (7)

1. An electronic door closer comprising: (a) a body defining an internal chamber; (b) a piston within the chamber, defining first and second cavities of variable size to either side of the piston, and a cavity within the piston, (c) fluid filling the cavities; (d) biasing means biasing the piston in one direction; (e) passageways for the flow of fluid between the cavities; and, (f) an electronic valve controlling flow of fluid and when closed holding the piston against the biasing means; wherein the electronic valve comprises adjustment means whereby the force required for manual release of a door held open by the closer may be adjusted.

2. An electronic door closer according to claim 1 wherein electronic valve comprises a magnetic coil and a core upon which it acts, and the adjustment means comprises means for adjusting the relative positions of the coil and core.

3. An electronic door closer according to claim 2, wherein the adjustment means comprises means for adjusting the position of the coil axially with respect to the core.

4. An electronic door closer according to claim 3, wherein the means for adjusting the position of the coil comprises an external thread around the core, a nut which engages on the external thread, the coil being a sliding fit around the core, and biasing means biasing the coil towards the nut.

5. An electronic door closer according to claim 4, wherein the nut is adapted for rotation by hand without the use of tools.

6. An electronic door closer substantially as hereinbefore described with reference to the accompanying drawings.

7. Any novel feature or novel combination of features as herein defined and/or shown in the accompanying drawings.