GB2214566A - Door actuator - Google Patents

Abstract

A powered door actuator (16) for opening an otherwise conventional hinged or sliding fire stop or other door comprises a driven winch, a cord (18) passing from the winch round a pully (20) on a relatively movable part of the (e.g. pivoted) door (10) before returning to a tension drum having a spring applying constant tension to the cord to take up stack. The door is drawn open by the cord when the winch is switched on, e.g. from a manually operated switch or an automatic sensor as a person reaches the door. The door is held open by braking means acting on the winch e.g. for a timed interval, and then swings closed e.g. under the action of a door closer when the winch is released. No special adaptation of the door is needed and it can be opened and closed from either side in the normal way without use of the actuator if desired. <IMAGE>

Description

DOOR ACTUATOR This invention relates to actuators for powered operation of doors. The term doorn unless otherwise qualified is used herein to include internal or external access doors, gates, shutters, or similar moveable closures either hinged or sliding.

The invention is particularly convenient and advantageous in its application to internal doors, particularly hinged doors, which are normally closed and are often required to be kept closed as fire and smoke stops at all times other than when someone is actually passing through them.

Such fire stop doors are required in institutions and multi-occupied buildings such as hospitals, old people's homes and blocks of flats. Despite the regulations it is very common to find that fire stop doors are kept wedged open because of the nuisance of passing through them, particularly if they have to be used by elderly or disabled people. Persons in wheelchairs or using walking frames have extreme difficulty or may find it impossible to manoeuvre through a hinged door which opens toward them particularly if it is in a confined space, e.g. at the end of a narrow passage and is urged closed by a "door closer" which often exerts strong resistance to opening. The disabled person may persevere with risk of falling or other injury or may have to call for assistance from otherwise busy staff.The same problems arise with service doors and the like which are passed through by people carrying loads or using trucks and trolleys..

It is known to provide power operated sliding or hinged doors e.g. operated automatically in response to approach of a person by means of a pressure mat, photocell detector or the like but most doors of this type are specially constructed to incorporate the actuating mechanism and are costly to manufacture, install, and maintain requiring special door f,rames, underfloor operating mechanism and the like. Thus they are only normally used for entrance doors to shops, offices and large buildings and are not suitable for internal doors.

The object of the invention is to provide a powered door actuator which is low in cost, simple and economical to install and maintain, which can readily be fitted to operate existing doors of almost all types without any substantial modifications or structural alterations, and which is effective, convenient and reliable in use.

According to the invention there is provided a powered door actuator including selectively operable power drive means, winch means operatively carrying an extendable and retractable flexible element connected in use between an anchorage at a fixed location and a portion of the door moveable relative to that location, control means responding automatically to a retract command or signal to apply drive from the drive means to the winch means for retraction of the flexible element to pull the door from a first to a second position and hold it at the latter position and responding automatically to a release command or signal to free the winch means permitting extension of the flexible element for the door to return to the first position, and tensioning means constantly taking up all slack in the flexible element in use as when the door is moved toward the second position without powered operation of the actuator.

Conveniently the actuator will be mounted at the fixed location to serve as the anchorage, the flexible element extending therefrom to said relatively moveable portion of the door but it is contemplated that the actuator might be carried on the door itself with the flexible element extending to a fixed anchorage remote therefrom.

Conveniently the winch means comprises a first rotatable drum to which one end of the flexible element is attached, said element being led round a pulley attached to said portion of the door in use, the other end being returned to the actuatorr, the tensioning means comprising a second rotatable drum of the actuator to which said other end of the flexible element is attached and which incorporates resilient means such as a spiral spring urging said second drum in a direction to constantly take up said slack.

While the flexible element may be or incorporate a flexible band eg a metal ribbon or textile webbing it is most conveniently a simple cord or wire which can easily be rigged and replaced and which can be led by means of pulleys in any required direction.

Preferably the control means includes a hold element automatically ceasing operation of the power drive means when the door reaches the second (e.g. fully open) position, conveniently said element is a swinging arm carrying a jockey pulley engaged by a bight of the flexible element so that it is angularly displaced as the door reaches the said position to operate a switch turning off the power drive while keeping the winch means braked to hold the door at said position. Said braking is conveniently effected by keeping a drive connection between the drive means and the winch means in engagement with the power drive turned off so that the inert drive means prevents extension of the flexible element, said connection being disengaged in response to the retract command or signal.The control means may include an adjustable or other timer for determining the interval between the retract and the release commands or signals.

An example of the invention is now more particularly described with reference to the accompanying drawings wherein Figure 1 is a diagram in plan view of a powered actuator installed for opening movement of a hinged door and Figure 2 is a detailed plan view of the actuator mechanism.

In Figure 1 a door 10 e.g. an internal fire stop door, is hinged for angular movement in an arc indicated at 12 between closed and fully open positions. Door 10 is shown at the end of and opening into a passage or corridor 14 which is quite narrow and as fire regulations require the door to be kept closed whenever possible it is fitted with a quite strong pneumatic or spring door closer of known kind (not shown).

It will be appreciated that if an elderly or disabled person e.g. in a wheelchair or using a walking frame wishes to go through the door from left to right as viewed in the drawing they have to manoeuvre in the narrow passage 14 to pull the door open toward them against the force of the door closer and then attempt to hold the door open sufficiently for them to get through which may well be difficult or impossible.

A power actuator unit 16 to be described in greater detail below is mounted on the wall of passage 14 substantially on a level with the top of door 10 and spaced along the wall from the hinged side of the door by a distance allowing the door to swing open parallel to the said wall. A strong flexible cord 18 e.g. of "NYLON" (Trade Mark) is led horizontally from unit 16 round a pulley 20 mounted near the top of the door remote from the hinge and back to unit 16.

The unit is electrically powered, e.g. from a mains supply, and its operation is initiated by a switch, e.g.

a push button 22 at a convenient location e.g. on the wall at the approach side to the door and/or an automatic sensor of known kind such as a pressure mat on the floor of passage 14 or a photo-cell detector device or the like. A person approaching down passage 14 will operate switch 22 or initiate automatic operation by triggering the sensor. Unit 16 winds cord 18 so that door 10 is swung to its open position, the door is held open for a predetermined period to allow time for the person to pass through, and the cord 18 is then released to allow the door to swing closed under the action of the door closer.

Unit 16 will now be described in greater detail with reference to Figure 2.

An electric drive motor 30 acts through an integral high ratio speed reduction gear box for positive rotation of a drive wheel 32.

Spaced from the latter is a freely rotatable winch drum 34 which has a first end of cord 18 anchored thereto, the cord being retracted by winding onto drum 34 when the latter is rotated clockwise as viewed in the drawing.

An idler wheel 35 is pivoted on a slide block 36 (or alternatively on a swinging arm) so that it can be shifted into and out of peripheral friction drive engagement with both wheel 32 and drum 34, when wheel 35 is so engaged drive will be transmitted from wheel 32 to the drum for powered rotation of the latter to retract cord 18.

Block 36 is loaded by a tension spring 38 acting in opposition to a solenoid 40 for selection engagement and disengagement of wheel 35.

On leaving drum 34 cord 18 passes round a guide pulley 42 which, in conjunction with lead eyes (not shown) through which the cord is threaded, ensure that it is kept in its proper alignment with drum 34.

Cord 18 passes round the pulley 20 on door 10 as referred to above and then returns to unit 16 passing round the back of a jockey pulley 44 to form a shallow bight before reaching a tension drum 46 to which the other end of the cord is attached. Drum 46 incorporates a clock type spiral torsion spring acting to apply a constant tensioning force to cord 18 by winding all or any slack onto drum 46. Again lead eyes (not shown) will be provided to ensure that the cord is not displaced from pulley 44 and is kept in its correct alignment with drum 46.

Jockey pulley 44 is journalled at one end of a swinging arm 48 conveniently fulcrummed on the same axis as drum 46, the other end of the ,arm remote from pulley 44 actuating a micro switch 50. Arm 48 extends substantially parallel with the wall on which the unit is mounted and is spring biased to urge pulley 44 towards the wall i.e. in opposition to the tension exerted by the bight of cord 18. The force of the arm tensioning spring 51 can be adjusted by means of a screw adjuster 52.

When the unit is inoperative idler wheel 35 is disengaged and cord 18 is fully unwound from winch drum 34, slack being taken up by and any excess length wound onto tension drum 46. Door 10 will be held closed by the door closer. If door 10 is opened manually in the normal way, e.g. by a person passing from right to left as viewed in Figure 1 so that they push the door open (which is very much easier to do) cord 18 will be wound onto tension drum 46 and, when the door is allowed to swing closed again, will be drawn off that drum. Thus the actuator does not impede or affect normal use of the door nor will any kind of movement of the latter adversely affect the actuator e.g. cord 18 cannot become slack or tangled.

When powered opening of door 10 is wanted the operation of manual switch 22 and/or of any pressure mat or like sensor switches current to motor 30 and at the same time actuates solenoid 40 to engage idler wheel 35 so that drive is transmitted to drum 34 so winding in or rotating cord 18. Initially any surplus cord will thus be unwound from tension drum 46 but as soon as this is taken up pulley 20 will be drawn towards the unit so that the door is swung open.

As door 10 reaches its fully open position (shown in broken lines in Fig. 1) pulley 20 will approach jockey pulley 44 . As the pull from cord 18 is now in line with the plane of the door the tension on the cord increases and arm 48 which is angularly displaced against the force of spring 51 to operate the micro-switch 50. This shuts off current from motor 30 so that rotation of drum 34 ceases, however idler wheel 35 is held in engagement with the drum periphery and wheel 32.

To ensure that the door is held open a one-way braking device acts on wheel 32. Said device, in this example, comprises a wedging idler roller 60 located by arms 62 which permit its axis to float to a limited degree. Its periphery bears on the periphery of wheel 32 and it also coacts with a fixed abutment 63 which is angled so that anti-clockwise rotation of wheel 32 causes roller 60 to wedge between the abutment and the latter periphery effecting locking wheel 32 and hence drum 34 to permit unwinding of the cord 18. Rotation of wheel 32 in the opposite, ie driving direction is not obstructed.

The braking effect may be supplemented, in some cases wholly provided, by the resistance of the high ratio gear drive and inertia of motor 30 when inactivated and/or other forms of one-way braking device could be used eg a ratchet and pawl device.

The door is thus safely held in the fully open position. If opening movement of the door should be obstructed this will also increase the cord tension to shift arm 48 and switch off the drive as above.

The control means of the unit includes a variably adjustable timer circuit connected with solenoid 40.

This is preset to provide a "hold" period long enough to permit the person pass through the door. At the end of the "hold" period solenoid 40 is switched to take wheel 35 out of drive engagement, winch drum 34 is free to rotate and the cord is unwound therefrom as the door swings closed under the action of the closer.

The control circuitry of the unit can be linked into a fire alarm or detector circuit of the building if required, thus if a smoke or fire alarm has tripped and the alarm circuit is activated power operation of the unit will be prevented and, if the unit should be holding the door open at that time, it will release to let the door close.A "fail safe" feature is that even if a door was held open by a unit spread of fire into the region thereof would quite quickly melt the nylon cord allowing the door to swing closed. r Where a fire door is permitted to be open through the day or at other predetermined periods and is to be closed at other times, e.g. at night the actuator can be used to hold the door open for a continuous period, in the event of a fire alarm it will be automatically released to let the door close and/or it can be automatically released from a central control point at a required time.

It will be appreciated that various refinements or modifications of the control means and associated manual controls or automatic sensors can be provided, for example an operating switch and/or pressure mat or the like could be provided quite simply on both sides of the door for power actuation by persons passing in either direction.

The construction of the unit itself may be varied, for example some other way of applying drive to and holding the winch drum 34 may be provided such as the incorporation of a brake element acting directly on the drum itself. The tensioning means may take other forms, for example it is possible that the tension and winch drums could be combined, a torsion spring being incorporated in or acting in conjunction with winch drum 34 itself to take up slack from the same end of cord 18 as that retracted by the winch, the separate tension drum being dispensed with.

The unit 16 can be positioned as convenient depending on the location. If there is no wall which the door opens towards as in Fig. 1 it may be necessary to use further guide pulleys, e.g. journalled on a fixture depending from a ceiling, to guide the cord 18 at the required angle. The unit may be used for opening and/or closing of many types of hinged or sliding closures; for sliding doors two units might be used, one for opening and one for closing.

The preferred unit is "fail safe"; only if operating current is available can it open the door or hold it open. If there is no current (from whatever cause) the door will be closed yet the unit in no way hinders or obstructs opening and closing of the door manually in the normal way.

Claims (16)

1. A powered door actuator including selectively operable power drive means, winch means operatively carrying an expendable and retractable flexible element connected in use between an anchorage at a fixed location and a portion of the door moveable relative to that location, control means responding automatically to a retract command or signal to apply drive from the drive means to the winch means for retraction of the flexible element to pull the door from a first to a second position and hold it at the latter position and responding automatically to a release command or signal to free the winch means permitting extension of the flexible element for the door to return to the first position, and tensioning means constantly taking up all slack in the flexible element in use as when the door is moved toward the second position without powered operation of the actuator.

2. An actuator as in Claim 9 wherein the winch means comprises a first rotatable drum to which one end of the flexible element is attached, said element being led round a pulley in use to form a connection between the anchorage and the relatively movable door portion, the other end of said element being returned to the actuator; a second rotatable drum constituting the tensioning means having said other end of the flexible element attached thereto, said second drum incorporating resilient means urging the drum in a direction to constantly take up said slack.

3. An actuator as in Claim 1 or 2 wherein the flexible element is a cord or wire.

4. An actuator as in Claim 1, 2 or 3 wherein the control means includes a hold element automatically ceasing operation of the power drive means in use when the door reaches the second position.

5. An actuator as in Claim 4 wherein the hold element is a swinging arm which is operatively engaged by a bight of the flexible element so that it is angularly displaced as the door reaches the second position in use, said displacement of said arm operating the power drive to cease retraction of the flexible element and brake the winch means to hold the door at said position.

6. An actuator as in Claim 5 wherein the power drive is controlled by a switch which is turned off by said angular displacement of the swinging arm.

7. An actuator as in Claim 5 or 6 wherein the braking of the winch means is effected by keeping a drive connection between the drive means and the winch means in engagement with the power drive turned off so that the inert drive means prevents extension of the flexible element, said connection being disengaged in response to the retract command or signal.

8. An actuator as in any preceding claim wherein the control means includes a timer for determining the interval between the retract and the release commands or signals.

9. A powered door actuator substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

10. A door installation comprising a door mounted for hinged or sliding movement relative to a door frame or other surround between open and closed positions; a door closer resiliently urging the door to the closed position; and a powered door actuator as in any preceding claim connected to act between a fixed location on the surround and a portion of the door movable relative to that location.

11. An installation as in Claim 10 wherein the actuator is mounted at the fixed location with the flexible element extending therefrom to said relatively movable portion of the door.

12. An installation as in Claim 10 or 11 wherein the door is a fire stop door.

13. An installation as in Claim 10, 11 or 12 wherein the door is hinged for swinging movement between open and closed positions and further including means for selective operation of the actuator from an approach to the door on the side which the door swings towards on opening.

14. An installation as in Claim 13 wherein said means is a manually operable switch and/or an automatic sensor switch responsive to the presence or passage of a person towards the door on the approach side.

15. An installation as in any one of Claims 10 to 14 including an automatic override linked to a fire alarm or detector circuit to release the actuator for automatic closing of the door if the actuator should be holding the door open when said circuit is activated.

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