GB2323125A

GB2323125A - Door closers:electrical control

Info

Publication number: GB2323125A
Application number: GB9705471A
Authority: GB
Inventors: Richard Aston
Original assignee: Freeman & Pardoe Ltd
Current assignee: Freeman & Pardoe Ltd
Priority date: 1997-03-15
Filing date: 1997-03-15
Publication date: 1998-09-16
Anticipated expiration: 2017-03-15
Also published as: GB2323125B; GB9705471D0

Abstract

In a door closer, spring 17 moves piston 16 to rotate pinion 20 to close a door, oil flowing from cylinder cavity 21 to piston cavity 18 via passage 23. The closer is held in its shown, door open, position by valve 36 urged by electric valve actuator 37 to prevent oil flow into cylinder cavity 22. If the electric supply to actuator 37 is cut, e.g. by activation of a fire alarm, valve 36 is lifted and allows oil to flow to cavity 22, enabling spring 17 to close the door.

Description

Description of Invention The invention relates to a door closer controlling the movement of a door to which it is fitted, and in particular, 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. However, the prior art electronic door closers suffer from a number of disadvantages, in particular, inferior performance due to wear and tear.

It is an object of the invention to provide an improved 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, the cavities being filled with fluid, (c) biasing means within the second cavity biasing the piston towards the first cavity, (d) passages between the first and piston cavities and the second and piston cavities respectively for the flow of fluid, including a main passage between the piston cavity and the second cavity, (e) an electronic valve controlling flow between the piston cavity and the second cavity, and wherein the main passage for fluid flow between the piston and second cavities, is external to the chamber.

The present invention provides the advantage that it is simpler and cheaper to manufacture than electronic door closers in the prior art.

Preferably the main passageway is within the body.

The electronic door closer according to the invention may further comprise adjustment means to permit adjustment of the passageways for use with alternative activation arm configuration. Preferably one bore is provided permanently communicating the main passageway with the piston cavity and two bores are provided, spaced apart along the length of the chamber, which communicate the main passageway with the piston cavity or the second cavity depending on the piston location. The adjustment means may comprise a plug portion which can be moved into one of the bores communicating between the main passageway and the piston cavity or the second cavity to close it off.

According to an alternative aspect of the invention there is provided a method of making an electronic door closer comprising the steps of: (a) machining a body with a chamber, a passageway alongside the chamber and bores therebetween, (b) inserting a piston into the chamber, defining a first cavity to one side of the piston and a second cavity to the other side of the piston, and a piston cavity, (c) filling the cavities with fluid, (d) sealing the ends of the body, and wherein, when the electronic door closer is in use, fluid flowing between the piston and second cavities, in either direction, flows through the passageway alongside the chamber.

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 O 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 one-way 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 electricity 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.

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 700 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.

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

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 within the second cavity biasing the piston towards the first cavity; (e) passageways communicating the first piston and cavities and the second and cavities for the flow of fluid, including a main passageway between the piston cavity and the second cavity; (f) an electronic valve controlling flow from the piston cavity to the second cavity, wherein the main passageway for fluid flow between the piston cavity and the second cavity is external to the chamber.

2. An electronic door closer according to claim 1 wherein the main passageway is within the body.

3. An electronic door closer according to claim 1 or 2 wherein it further comprises adjustment means to permit adjustment of the passageways for use with alternative activation arm configurations.

4. An electronic door closer according to claim 3 wherein one bore is provided permanently communicating the main passageway with the piston cavity and two bores are provided, spaced apart along the length of the chamber, which communicate the main passageway with the piston cavity or the second cavity dependant on the piston location.

5. An electronic door closer according to claim 4 wherein the adjustment means comprises a plug portion which may be inserted into one of the bores communicating the main passageway with the piston cavity or the second cavity, to close it.

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

7. A method of making an electronic door closer comprising the steps of: (a) machining a body with a chamber, a passageway alongside the chamber and bores therebetween; (b) inserting a piston into the chamber, defining a first cavity to one side of the piston and a second cavity to the other side of the piston, and a piston cavity; (c) filling the cavities with fluid; (d) sealing the ends of the body, and, wherein, when the piston moves axially within the chamber, fluid flowing between the piston cavity and the second cavity, in either direction, flows through the passageway alongside the chamber.

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