GB2067656A - Closing control for a double door, particularly a fire door - Google Patents

Abstract

A closing control for a double door comprising a first leaf (11) and second leaf (12), to ensure that the first leaf (11) closes before the second leaf (12), comprises respective door closing means (13) for the leaves (11, 12), which door closing means (13) will hold the respective door leaf (11 or 12) in an open position if the leaf is opened beyond a determined angle, and an abutment arm (20) movable between an initial position (shown dotted) and an extended position (shown in full lines). The closing control includes electro-magnetic holding means (26) to maintain the arm (20) in its initial position until a control signal is generated by a closing movement of at least one of the leaves (11, 12) of the door and for operation of at least one of the door closing means (13). An electronic control circuit is provided for sensing operation of the door closing means (13) and is connected also to the holding means (26) and to a fire detector such as a smoke sensor. <IMAGE>

Description

SPECIFICATION Closing control for a double door, particularly a fire door The invention relates to a closing control for a double door, particularly a fire door, the double door comprising a first door leaf and second door leaf which co-operate in a manner such that the first leaf must move to its closed position before the second door leaf moves to its closed position for correct closing of the double door.

In such a closing control the leaves are each provided with a door-closing means which can be blocked electro-magnetically to prevent automatic closing from beyond a determined angle of opening of the respective leaf, wherein the closing control comprises a stop arrangement in the form of a spring-loaded abutment arm, which is pivotable about an axis of rotation fixed to a wall or lintel and can follow the first leaf, after opening thereof, from an initial rotary position substantially parallel with the wall or lintel into an extreme extended position, the arm normally being kept in said initial rotary position by a holding means which can be changed electro-magnetically to a releasing condition, and wherein the end of the abutment arm, in the extreme extended position, lies in the path of an opposing stop seated on the second leaf.

Double doors, particularly those acting as fire barriers, have to be equipped with closing means associated with each leaf, to ensure that the leaf is securely closed in the case of fire. The doorclosing means are constructed so that they hold their associated leaf in the open position, by means of an electro-magnetically supported valve member, from a given door-opening angle of e.g.

900. The valve member actuated by the electromagnet frees a return passage when the electromagnet is de-energised. Only when this happens can a spring, which acts as a drive means in the closing direction, guide the leaf associated with the door-closing means back into its closed position. These door-closing means are usually controlled by fire detectors, such as smoke monitors. Double fire doors usually overlap in their middle portion, that is to say the first leaf has a stop for the second leaf. A correct closing sequence for tight sealing is necessary if the leaves of such a double door are to be closed correctly. Closing controls of the above mentioned kind are required for this purpose, since they can ensure the sequence of movements of the two leaves into the closed position as required for the above mentioned correct closing.A certain sequence of closing movements for both leaves is necessary if the second leaf, which generally mounts a catch, is not to reach its closed position until after the first leaf, which has an abutment thereon for the second leaf and generally also has a catch plate, has closed. The abutment arm of the closing control disposed above the door is used for this purpose. The arm is spring-loaded and, following the opening movement of the first leaf, moves until the abutment arm has reached its extreme extended position. Here it can support the second leaf so that before it is closed the first leaf and abutment arm first reach their closed and initial rotary position respectively, after which the second leaf can be closed.Thus at every opening movement of the first lead the abutment arm splays out from its initial rotary position parallel with the wall or lintel, and projects from the plane of the wall or lintel. Particularly in buildings used mainly by children, such as schools, youth hostels or the like, the projecting abutment arm is likely to be misused, e.g. as a bar for gymnastics. Such use is not beneficial to the arm, and if so used operation of the closing control can thereafter no longer be guaranteed.

According to the invention there is provided a closing control for a double door, particularly a fire door, comprising a first leaf and a second leaf which co-operate in a manner such that the first leaf must move to its closed position before the second leaf moves to its closed position for correct closing of the double door, in which the leaves are each provided with door-closing means which can be blocked electro-magnetically to prevent automatic closing from beyond a determined angle of opening of the respective leaf, wherein the closing control comprises a stop arrangement in the form of a spring-loaded abutment arm, which is pivotable about an axis of rotation fixed to a wall or lintel and can, after opening movement of the first leaf, move from an initial rotary position substantially parallel with the wall or lintel into an extreme extended position, the arm normally being kept in said initial rotary position by a holding means which can be changed electro-magnetically to a releasing condition, wherein the abutment arm, in its extreme extended position, lies in the path of an opposing stop seated on the second leaf, and wherein said holding means for the closing control can be changed to its releasing condition to enable the abutment arm to move to its extreme extended position by a control signal resulting from closing movement of at least one of the leaves of the door and/or from operation of at least one of said door-closing means.

Thus the abutment arm of the closing control is kept in its initial rotary position parallel with the wall -- independently of any opening movement of the first leaf - until the extreme extended position of the arm is required for controlling the closing sequence.

During the opening movement of the first leaf the abutment arm of the closing control does not move automatically to its extreme extended position, since the holding means supports the arm in its initial rotary position. Only when one of the two leaves moves in the closing direction is the holding means transferred to a releasing condition by a control signal, so that the abutment arm is released and swings into its extreme extended position as a result of its spring loading.

Thus the closing movement of the second leaf will always be stopped until the first leaf has reached a closed position in advance of the second leaf. On further closing movement of the first leaf, the latter guides the abutment arm with a cam, back to its initial rotary position, and it is again fixed in that position by the holding means. Since the first leaf is moved to its closed position first, the closing sequence which takes place enables the two-ieaf, i.e. double, door to be shut tightly. The holding means used to fix the abutment arm in its initial rotary position may be a holding magnet provided with a magnetic coil.It is also possible to use an electro-magnetically operated holding means instead of an electro-magnet holding the abutting arm directly; the holding means could comprise e.g. an electro-magnetically locked blocking slide which would hold the abutment arm mechanically in its initial rotary position. The abutment arm of the closing control would not be extended until the closing movement of one of the leaves of the door had been initiated.

When the first leaf is closed, the abutment arm is kept in its initial rotary position by the cam on the first leaf, even when the holding means has been transferred to its releasing condition. When the first leaf is open and the abutment arm in its initial rotary position, however, it is essential -- particularly when the closing movement of the second leaf has been initiated -- that the abutment arm of the closing control should be moved into its extreme extended position ready for operation, since an exclusive closing movement of the first leaf will anyhow only allow a correct closing sequence of the leaves.To allow for satisfactory closing sequence control in any event, even when the closing movement is initiated first at the second leaf, it is preferably provided that the control signal for the holding means can be initiated by the movement of the second leaf and/or by operation of the doorclosing means of the first leaf. It is advantageous for the change in the electro-magnetic field, which takes place during a closing movement of one of the leaves, and the resultant changes in current of the door-closing means associated with that leaf to be used as a control impulse.

In order that the eiectro-magnets, which are provided in any case, can be used for control purposes, it is preferably provided that the control signal for the holding means can be initiated by the movement of at least one leaf of the door and/or by operation of at least one door-closing means, by change in an electro-magnetic field and a resultant change in current.

The current change switches off the electro magnetically actuated holding means, preferably via an amplifier and a monostable circuit, so that well defined switching for the holding means is obtained even when the current change is slight.

Advantageously the control current for the doorclosing means which can be secured electromagnetically flows through a first transistor, the base of which is initially energised, at the instant of connection, through a parallel arrangement comprising a resistor and a capacitor When the first transistor has become conductive, the base is energised again by a second transistor, the base of which can be energised by the control current flowing through the first transistor. It is particularly advantageous to have simultaneous current monitoring of the electro-magnets when the current shows a tendency to drop.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a front elevation of a double fire retarding door, with a closing control according to the invention and with top door closing means associated with each leaf; Figure 2 is a front elevation of a double door, with a closing control according to the invention and with bottom door-closing means associated with each leaf; Figure 3 is a plan view of the double fire retarding door of Figure 1, with the moving leaf held ajar during its closing movement by an abutment arm of the closing control; Figure 4 is a longitudinal section through a top door closing means of the kind indicated in Figures 1 and 3;; Figure 5 is a section taken on line VIll-VIll in Figure 2, through a bottom door-closing means of the kind indicated in Figure 2; and Figure 6 is a circuit diagram for the control appliance required to process a control signal.

In the examples shown in Figures 1 and 2 a door with two leaves, namely a first leaf 11 and a second leaf 12, is disposed in an aperture in a wall or in a frame fixed for example between two walls in a corridor. Both the first leaf 11 and the second leaf 12 are equipped with door-closing means, the leaves in the Figure 1 example each being joined to a respective top door-closing means 13, which are fixed e.g. to the door frame and operatively connected by a respective rod mechanism 14 to the appropriate leaf 11 or 12.

In the example shown in Figure 2 a respective bottom door-closing means 1 5 is associated with each leaf 11 and 12. Its closing shaft acts directly upon the respective door leaf by projecting into a non-circular socket in the bottom of the door, the axis of pivot of the door being coaxial with the closing shaft.

As will be explained in greater detail below, both the upper closing means 13 and the lower closing means 1 5 can be held in a locked position by an electro-magnetically supported valve, from a given opening angle of each leaf.

The second leaf 12 is provided with a door catch and an operating handle 1 6 therefor and has a rabbeted web 1 7. The first leaf 11 carries an abutment web 1 8. On the lintel of the frame, above the leaves 11 and 12, there is a closing control 19, its essential component being an abutment arm 20. The arm 20 is mounted in a bearing arrangement 21 in such a way that a torsion spring surrounding its bearing journal biasses the arm for movement outwardly away from the frame to an extreme extended position.

The free end of the arm 20 carries a shock absorber 22 equipped with springs. The bearing arrangement 21 restricts the pivoting path of the arm 20 in known manner and in such a way that when the abutment arm 20 is in its extreme extended position (Figure 3) it extends into the pivoting path of a stop 23 fixed to the second leaf 12. When the abutment arm 20 is in its operative position, it holds the leaf 1 2 open until a carn 24 on the first door leaf 11 abuts the arm 20 and pressures it back to its initial rotary position in which it is parallel with the wall or the lintel of the door frame. As will be seen particularly from Figures 1 to 3, an electro-magnet operating as a holding means 26 is fixed to the frame and can hold the abutment arm 20 in its initial position.

When current is flowing in the electro-magnet the arm 20 is held in its initial position parallel with the wall by the eiectro-magnet 26. The electromagnet 26 is connected by leads to a control appliance 33, which is wired (a) to a fire detector 25, e.g. a smoke monitor or the like disposed above the door frame and (b) to the door-closing means 13 or 1 5.

The upper door-closing means 13 may e.g. be as disclosed in British Specification 1 531 869. In such door-closing means 13, and with reference to Figure 4 of the accompanying drawings, a closing shaft 34 is coupled to a door leaf either directly or by a rod mechanism similar to the rod mechanism 14. On an opening movement of the leaf a pinion 35 of the closing shaft 34 moves a piston 36 (Figure 4) to the right, the piston in known manner having two heads 38 and 39 separated by a toothed rack 37.The cylinder chamber, which is located to the right of the piston head 39 and which contains a compression spring 40 becomes smaller in the process, and the pressure medium flows through an annular slot between a bore 41, with a seal therein, of the piston head 39 and a stepped down portion 42 or the rod 43, into the part of the cylinder bore containing the rack 37, and through a non-return valve 44 to the part of the cylinder bore to the left of the piston head 38. The flow is maintained until a transitional part 45 of the rod 43 has entered and sealed the annular seal of the bore 41. In this way the above mentioned path for the fluid, from the chamber to the right of the piston head 39 to the chamber to the left of the piston head 38, is closed.The piston 20 can nevertheless still be moved to the right against the force of the spring 40, i.e. the door can be opened further, since fluid from the space to the right of the piston head 39 can pass through a bore 46 in a plug 48 and through a non-return valve 47 into an annular passage 49, and from there through bores 50 to 54 into the region to the left of the piston head 39, and through the valve 44 to the space to the left of the piston head 38. The door can thus be fully opened by by-passing a holding valve member 56 supported by an electro-magnet 55.

If a door-opening movement which compresses the spring 40 ceases before the transitional portion 45 enters the bore 41, then the partially open door, when released, will close automatically by the action of the spring 40, which loads the piston 36 and thus acts on the closing shaft 34 in the closing rotary direction, since the pressure medium can flow back through the annular gap between the seal in the bore 41 and the stepped down portion 42 and through the bores 50 to 54.

If the door-opening movement is not discontinued until after the rod portion 43 has entered the bore 41, i.e. until it is blocking the passage through the piston head 39, then further operation is determined by the holding valve 56. If this valve is supported in the blocking position by the armature of the electro-magnet 55, fluid cannot flow away from the whole area to the left of the piston head 39, since the only bores available are those where the last one is closed by the valve member 56. The door is accordingly held in the open position.If an external closing force is exerted on the door while in such an open position, and generates high enough pressure in the space to the left of the piston head 39, this pressure will also be present in the bores 50 to 54, the annular slot 49 and therefore bores 57 and 58, and will push back the valve member 56 with the armature, so that the fluid can pass through a transverse bore 59 and the bore 46 to the space to the right of the piston 36, and the door will close. However, the magnetic field is changed in the process and there is a change of current, which reaches to control appliance 33 as a control signal.This causes the control appliance 33 to deenergise the electro-magnet of the holding means 26, so that the abutment arm 20 of the closing control 1 9 is released from the magnet, and the torsion spring of the bearing 21 swings the arm 20 out into its extreme extended position. As described above, this prevents the second leaf 12 from closing before the first leaf 11 closes. In the event of the electro-magnet 55 of the top doorclosing means 1 3 being de-energised by means of the fire detector, the change in the magnetic field will be transmitted in the same way to the magnet of the holding means 26 for the closing control 19, so that its abutment arm 20 will move to its extreme extended position in the manner described above.

The bottom door-closing means 1 5 shown in Figure 5 is known from British Specification 1 552 257 and is comparable in its operation with the top door-closing means 13 previously described. With reference to Figure 5 of the accompanying drawings, the means 1 5 comprise two units, namely a door-closing means 60 and means 61 for holding the door open; each is accommodated in a housing. The two housings are arranged together in a so-called cement box below the hinge region of the respective leaf of a door. Both the housing of the door-closing means 60 and that of the means 61 for holding the door open are filled with a pressure medium and accordingly are provided with covers which can be tightly sealed. A closing shaft 62 is mounted in the door-closing housing; it has a crank pin 63, acted on by a lever mechanism 64, which is impinged on by a closing spring 65 and by a hydraulic damping means 66.

A cam 68 is formed as a longitudinal side edge of a lever 67 of the lever mechanism 64 connected to the closing shaft 62; the cam 68 has a constant slope relative to the direction of movement of the lever 67. The cam 68 is provided in a region which takes in the wider-open positions in which the door may be required to be secured. A further cam 69 adjoins the cam 68 at one side. When the door is opened the cam portions 68 and 69 of the lever 67 successively move past a supporting member 71, which is in the form of a slide with a roller 70 at the end. In regions near to the closed position the roller 70 is opposite the cam 69 of the lever 67, while with wider-open angles the cam 68 interacts with the roller 70.The supporting member 71 is held in a bush so that it cannot turn but can move longitudinally; the bush extends through the housing and projects from it.

A cylinder 72 is provided in the housing of the means 61 for holding the door open, and a piston 73 can slide into the cylinder against the tension of a spring 74. A non-return valve 76 opens towards a working chamber 75 of the pistoncylinder arrangement. When the piston 73 moves to the left, driven by the spring 74, the valve 76 accordingly lets pressure medium flow out of the interior of the housing into the working chamber 75. The medium flows through a bore 77 in the bottom of the cylinder 72; this extends into a smaller bore 78, against the end of which a valve member 79 can be pressed with a sealing action.

The valve member 79 has an annular collar which considerably overlaps the width of the bore 78 and which covers a passage 80 in the closed position of the member 79. The end of the member 79 away from the bore 78 is acted on by the armature of an electro-magnet 81. The pressure medium can flow out of the working chamber 75 through the bores 77, 78 provided that the valve member 78 allows it to.

A bell-crank lever 82 can pivot about a journal fixed to the housing and is applied to the piston 73 by means of a roller. The lever 82 acts on the end of the supporting member 71 by means of a further roller.

In the closed position of a door to which the closing means of Figure 5 is applied, the piston 73 is pressed into the cylinder to the maximum against the tension of the spring 74. The electro magnet 81 is energised, so that the valve member 79 is applied to the end of the bore 78 and seals it. During the opening of the door, while the cam 69 is moving past the roller 70 of the supporting member 71, the closing spring 65 is tensioned and the damping piston moved to the left so as to enlarge the working space of the damping means.

When the door is released from small opening angles corresponding to the cam 69 on the member 67, it closes automatically by the action of the spring 65, since the securing means can come into action only when the cam 68 of the lever 67 is interacting with the supporting member 71. Then, with the opening angle increasing, the supporting member 71 is moved forward within its guide, by the action of the spring 74 acting on the piston 73; the working space of the piston-cylinider arrangement grows larger and takes in pressure medium through the non-return valve 76. If the door is released while the electro-magnet 81 is energised, i.e. while the valve member 79 is held in its closed position, the supporting member 71 would have to recede in accordance with the slope pn the cam 68, for a closing movement of the door.However, this is prevented by the fact that fluid cannot escape from the working chamber 75 because the bore 78 is blocked. The supporting member 71 is thus held in whatever longitudinal position it has reached when the door is opened, by means of the lever 82. A closing movement of the door is prevented in a similar way. Only when the electromagnet 81 is de-energised, can the valve member 79 free the outlet of the bore 78, to allow pressure medium to flow out of the working chamber 75 of the piston-cylinder arrangement. The closing movement of the door, driven by the spring 65, is released in this way.

If the door, while open and being held open, is acted on forcibly in the closing direction while the electro-magnet 81 is energised, the fluid pressure in the working chamber 75 of the piston-cylinder arrangement can rise so as to lift the valve member 79 out of the blocking position against the force of the electro-magnet 81. The pressure then acts on the larger area of its annular collar and transfers the valve member 79 securely to an open position, the means for holding the door open becoming inoperative. The door will usually reach the closed position even if the external force is effective for only a short time, because the fluid pressure of the piston-cylinder arrangement thereafter acts on the area defined by the diameter of the annular collar, which is larger than the cross-section of the bore 78.

With the bottom door-closing means described, there is accordingly a change in the field of the electro-magnet 81 when a movement to close a leaf of the door is initiated, and a change in current results. When the leaf is forcibly closed from the open position, the armature of the electro-magnet 81 is moved by means of the valve member 79.

The resultant change in the magnetic field produces a change in current, which is used as a control signal for the holding means 26 of the closing control 19. If the interruption in the current of the electro-magnet 81 is initiated by the fire.

detector 25, the electro-magnets will be disconnected and the leaf of the door will be closed in the correct way.

Significant details of a circuit for processing the control signal can be seen in Figure 6, where the circuit has various connecting points. The points R and Mp, with an earth connection, are provided to connect the appliance to mains power.

The smoke monitoring system, which terminates the blocking of the door-closing means when fire is sensed, is connected to points 1 and 2. It should be mentioned that the smoke monitoring system is connected without any potential. The terminals 6, 7, 9 and 10 connect the two door-closing means, the first door-closing means being linked to the terminals 7 and 10 and the second to the terminals 6 and 9. The terminals 5 and 8 connect the electro-magnetically operated holding means 26.

As will be seen from the diagram, the circuit can be divided into individual sections, namely a current supply section A, an amplifying section B, a disconnecting section C for the holding means and a control section D for the door-closing means, The voltage tapped from the mains is transformed to a lower level by a transformer Tr and then rectified with a fuse F1 interposed, by a bridge rectifier D1, D2, D3, D4 and DC voltage obtained then being smoothed by capacitors C1, C2 in parallel with the bridge rectifier. The resultant voltage is then applied to a voltage stabiliser Cm. the stabiliser IC1 keeps the voltage constant, and a potentiometer P1 connected to the stabiliser IC1 enables the voltage level at the output from the stabiliser to be adjusted.

The amplifying means B comprises an operational amplifier IC2. This receives its supply voltage through the terminal 2 of the appliance. It should be mentioned that the amplification of the operational amplifier can be adjusted by means of a potentiometer P2. In the example illustrated amplification by 40 to 100 times is possible.

Capacitors C7, C9 and Cl 1 and C12 are filters, which filter out undesirable signals which might interfere with the operation of the appliance.

The disconnecting means C is provided as a mono-stable circuit and its construction is known per se. All that need be said here is that the stable position of the circuit is reached when a transistor T3 becomes conductive. A transistor T4 is then blocked, while transistors T5 and T6 are conductive.

The starting section D of the circuit for the two door-closing means comprises a transistor T2. Its base is connected via the resistors R8 and R10 to the terminai 2 of the smoke monitoring system. A capacitor C10 is connected in parallel with the resistor R8. A further transistor T1 is connected in parallel with the capacitor C 10, its base being connected to the collector of the transistor T2, and a measuring resistor R9 being arranged between its emitter and its base.

The door-closing means which can be electromagnetically secured are normally applied to the controlled DC supply. When the appliance is switched on, provided that the smoke monitoring system is in its operative position, i.e. the two terminals 1 and 2 are electrically connected, the capacitor C10 is charged and supplies the base of the transistor T2 with a pulse, by way of the resistors R8 and R1 so that the transistor T2 itself conducts. This creates a voltage drop at the measuring resistor R9, so that the transistor T1 also becomes conductive and biasses the base of the transistorT2 so that the transistor R2 remains conductive. It should be mentioned here that the measuring resistor R9 is designed so that, if the door-closing current drops below a given value, the transistor T2 will be switched off.The change in the control current could be caused by failure of one of the two door-closing means, making the control current drop to half of its previous value and causing disconnection. Reconnection is not possible until the interruption has been dealt with and the entire current of the control means has been disconnected for at least 90 seconds.

The passage of current to the magnetically operated holding means will now be described.

The current required for the purpose is tapped from the connecting point 2 for the smoke monitoring system and flows through a transistor T6 to the connecting point 8 and back through the connecting point 5. The base of the transistor T6 is energised by means of a transistor T5, the base of which is in turn energised by the two doorclosing means dependent on the control current.

As already mentioned, the transistor T4 of the monostable circuit is normally blocked. In this way the current can flow to the base of the transistor T6 through a resistor R17 and the collectoremitter of transistor T5. If the transistor R2 should be blocked, i.e. if there were to be no current flowing to the door-closing means, then the transistor T5 would be in its blocked condition.

The transistor T6 thereby also goes into its blocked condition, so that the magnetically operated holding means is transferred to its released condition. The same thing happens when the transistor T4 becomes conductive, for then the base of the transistor T6 is no longer energised via the collector-emitter of T5, and the transistor T6 thus moves into its blocked condition.

The releasing of this last mentioned control will now be described. When the doors are moved from their held open position towards their closed position, a pulse-like change of current is brought about by the magnet responsible for securing the door-closing means. The change in current passes through the capacitor C6 to the input of the operational amplifier IC2. Here it is further amplified and any interfering frequencies are filtered out by filter means C7, C9 and C 11, C 12.

The filtered pulse signal then passes through a diode D7 to the base of the transistor T3. The resultant negative voltage pulse of short duration blocks the transistor T3, thereby at the same time energising the base of the transistor T4 and causing the transistorT4 to conduct. As a result a pulse appears at the collector of the transistor T4; it is passed through the capacitor C13, as a negative pulse, to the base of the transistor T3 and keeps the transistor T3 blocked. As already mentioned, the conduction of T4 results in the blocking of the transistor T6 and thus in the transfer of the holding means to its released condition.

The capacitor C13 is applied to the supply line via the resistor R12, as that it can be discharged through this resistor. As soon as a positive voltage is again applied to the base of the transistor T3, T3 becomes conductive again. T4 is blocked again and the mono-stable circuit is tripped back to its stable position. Although the electro-magnet of the holding means is supplied again, the springloaded abutment arm has been able to swing out and thus control the closing sequence of the doors, because of the previous release. If the first leaf should already be in its closed position the abutment arm will be secured thereby and will not move. When the holding means is reoperated the abutment arm will then be locked again.

It should be mentioned that when the smoke monitoring system responds, i.e. when the connection between the terminals 1 and 2 is broken, the holding means 26 is similarly transferred to a released condition since it is then similarly not being supplied with current.

When a door-closing means is acted on, the other door-closing means and the holding means 26 are also disconnected from the supply. In order to have the control means ready to operate again, the disconnection of current at one door-closing means must be terminated, and the current supply of the control means itself interrupted for a certain time the interruption may take place via the potential-free contacts 1, 2 of the smoke monitoring system.

It should finally be explained that the diodes D6 and D8 are provided to leak off any troublesome induced voltages without adversely affecting the control means.

As already mentioned, the constructions described and illustrated are only examples of the invention. The invention is not restricted to these, and many variations and different embodiments are possible within the scope of the appended claims. Thus it is conceivable, instead of obtaining the control signal directly from the electromagnets of the door-closing means, to use control signals, e.g. from potentiometers, magnistors or piezo-electric crystal elements which sense movement of the leaves of the door.

Claims (6)

1. A closing control for a double door, particularly a fire door, comprising a first leaf and a second leaf which co-operate in a manner such that the first leaf must move to its closed position before the second leaf moves to its closed position for correct closing of the double door, in which the leaves are each provided with door-closing means which can be blocked electro-magnetically to prevent automatic closing from beyond a determined angle of opening of the respective leaf, wherein the closing control comprises a stop arrangement in the form ofa spring-loaded abutment arm, which is pivotable about an axis of rotation fixed to a wall or lintel and can, after opening movement of the first leaf, move from an initial rotary position substantially parallel with the wall or lintel into an extreme extended position, the arm normally being kept in said initial rotary position by a holding means which can be changed electro-magnetically to a releasing condition, wherein the abutment arm, in its extreme extended position, lies in the path of an opposing stop seated on the second leaf, and wherein said holding means for the closing control can be changed to its releasing condition to enable the abutment arin to move to its extreme extended position by a control signal resulting from closing movement of at least one of the leaves of the door and/or from operation of at least one of said door-closing means.

2. A closing control according to claim 1, in which the control signal for the holding means of the closing control can result from movement of the moving leaf and/or by operation of the doorclosing means of the second leaf.

3. A closing control according to claim 1, in which the control signal for the holding means can result from movement of at least one leaf of the double door and/or by operation of at least one of the door-closing-means, by changing an electromagnetic field with a resultant change in current.

4. A closing control according to any one of claims 1 to 3, in which the control signal deenergises the electro-magnetically operated holding means by way of an amplifier and a monostable circuit.

5. A closing control according to any one of claims 1 to 4, in which the control current for the door-closing means, which is or can be secured electro-magnetically, flows through a first transistor, the base of which can be energised at the instant of connection, initially via a parallel arrangement comprising a resistor and a capacitor and when the first transistor has become conductive, the base is energised again by a second transistor, the base of which can be energised by the door-closing control current flowing through the first transistor.

6. A closing control for a double door, particularly a fire door, substantially as hereinbefore described and illustrated with reference to Figures 1.3. 4 and 6 or Figures 1,2, 5 and 6 of the accompanying drawings.