WO1999025944A1

WO1999025944A1 - Door closure and locking

Info

Publication number: WO1999025944A1
Application number: PCT/GB1998/003456
Authority: WO
Inventors: Alan Geoffrey Burchell
Original assignee: Stockton Engineering Limited
Priority date: 1997-11-18
Filing date: 1998-11-17
Publication date: 1999-05-27
Also published as: GB2332019A; GB2332019B; GB9724227D0; GB9825071D0; AU1167099A

Abstract

A door locking system for a vertically hung door (1), comprising at least two elongate axially displaceable locking elements (13) mounted to the door (1) and separately resiliently loaded towards their door locking engagement with positionally fixed locking elements (16), locking elements operator means (23-29; 55-64) adapted for manual or remote operation, and means (22) for operationally coupling the locking elements with said operator means, the arrangement being such that actuation of the operator means causes simultaneous operation of the displaceable locking elements (13) against the resilient loading (19) thereof when it is required to unlock the door and to allow the movable elements (13) separately to engage their associated fixed locking elements when the door is in its closed lockable position.

Description

DOOR CLOSURE AND LOCKING

This invention relates to the closing and locking of large area doors such as are commonly used with premises such as wharehouses and premises having entrances intended to provide large area entrances such as are provided for garages .

In particular, the present invention is concerned with doors which are each pivotable about a horizontal axis located at the upper region of the door in such manner that in order to open the door the latter is swung upwards about its pivot axis and in the opposite direction to close the door.

It will be understood that in some constructions the actual mounting of the door involves counterpoising arrangements which allow the actual pivots provided on the door to displace to allow the top of the door to displace inwardly into the premises with which the door is associated to facilitate the actual handling of the door during the door opening and closing operations and to enable to door to lie ultimately in a generally horizontal position when fully open .

During the closing of such doors the upper part of the door moves forward to bring the door into a required vertical setting .

It is well known to provide for such doors as above mentioned with a door closure retaining and locking means in the form of a horizontally arranged closure system involving, in some applications, a rotatable pivot unit, having an integral locking mechanism, such as a key operable lock, centrally positioned widthwise of the door at a level convenient for manual turning of the pivot unit by a person handling the opening and closing of the door.

An inner end of each of two oppositely directed bars or rods are pivotally connected to the rotatable pivot unit. The outer ends regions of these rods or bars are engaged with guides located at the sides of the door in such manner that the outer ends of the two rods or bars are able easily to slide therein to project outwarddly when in their locked positions to latch behind the door frame with the strnength of the bar against bending providing the sole door holding locked resistance.

The arrangement as so far discussed is such that on rotating the pivot unit in one sense, i.e., clockwise, the rotation of the pivot unit simultaneously moves the rods or bars outwardly to their projecting positions. On turning the pivot unit in the opposite sense i.e, anti-clockwise the rods or bars are so displaced as to draw the the outer ends inwardly so that these outer ends no longer project outwardly of the door sides.

It will be understood from the forgoing that when the doors ^are closed and the associated key is used to lock the locking mechanism against rotation of the pivot unit the door is held in its locked position by the engagement of the outer ends of the rods or bars in the engagement with the door frame.

It has been found that total reliance on this mode of retaining large area doors in their locked positions fails to provide adequate security in endevouring to prevent unauthorised opening of the doors. Also in tests have shown that since the bottom and more particularly the corner regions of the door can be free enough for a person to be able to flex/deflect/lever out the door bottom/corners relative to the remainder of the door, (this condition has been noted to be a possibility with garage doors of both private and comraerical properties) it is relatively easy for a would be intruder to exert leverage under a door to 'spring' the bar or rod outer ends out from engagement with the engagement and location means on the door frame or adjacent wall and thereby be able to open the door at least sufficiently to gain access .

It is an object of the present invention to provide a large area door closed position retention arrangement which at least reduces the ease by which the bottom and particularly the corners of a door can be displaced with respect to an adjacent fixed location such as a door frame wall or other location whilst the door is in its closed and locked condition .

Broadly according to the invention there is provided a door locking system for a vertically hung door, comprising at least two elongate axially displaceable locking elements mounted to the door and separately resiliently loaded towards their door locking engagement with positionally fixed locking elements, locking elements operator means adapted for manual or remote operation, and means for operationally coupling the locking elements with said operator means, the arrangement being such that actution of the operator means causes simultaneous operation of the displaceable locking elements against the resilient loading thereof when it is required to unlock the door and to allow the movable elements separately to engage their associated fixed locking elements when the door is in its closed lockable position. Broadly, according to a further aspect of the invention, there is provided a door closure retention and locking arrangement including means for locking vertically opposite corner or central regions of a door that is vertically hung for opening and closing displacement about a horizontal pivot axis adjacent the upper part of the door.

Preferably, the movable locking member is mounted in a bracket assembly adapted for connection to the door, the bracket member including a back plate and upper and lower outwardly projecting parts serving as guides for the bolt member, and wherein the resilient loading of the bolt member comprises spring means provided on that part of the bolt member located between the projectin parts.

Conveniently each movable locking member is operationally coupled by its associated linkage to a linkage connection element associated with pivot means, the arrangement being such that in order to unlock the door following release of the locking mechanism the pivot is turned in the appropriate sense to cause each linkage to withdraw against the esilient loading thereof its associated locking member from its associated fixed locking member, thereby to free the door for opening.

Conveniently, the upper and lower locking members are operationally coupled by way of oppositely directed bars, rods, cables or the like, to pivot means incorporating a lock mechanism, the arrangement being such that in order to unlock the door following release of the locking mechanism the pivot is turned in the appropriate sense to cause the rods, bars, cables or the like to withdraw the locking members, against the resilient loading thereof, from their locking engagement with the associated locating and locking points thereby to free the door for opening. For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawings in which:-

Figures 1 and 2, very schematically illustrate the concepts of the invention as applied positionally locating and locking of a corner of a door. As will be noted the

Figures only schematically illustrate a fragmentary portion only of the door and frame, the Figure 1 illustrating the locking arrangement of the invention when in a door locking setting and the Figure 2 illustrating the locking arrangement when in its door releasing setting;

Figure 3 schematically illustates a variation of the locking arrangement of Figures 1 and 2;

Figure 4 schematically illustrates a first embodiment of a door locking installation in which it is required to provide for a operating handle that is located centrally of the width of the door and is operationally connected simultaneously to operate four locking means located one to each corner of a door;

Figure 5 schematically illustrates a second embodiment of an installation where it is required to provide for a operating facility located centrally of the width of the door and which is operationally connected simultaneously to operate four locking means located one to each corner of a door.

Figure 6A and Figure 6B are perspective views of details of a secondary locking arrangement;

Figure 6C is a sectional plan view of the secondary locking arrangement when installed on a door and door frame as indicated in Figure 1 ; Figure 6D illustrates the application of the secondary locking means to a door locking system as shown in Figure l;

Figures 7A to 7E schematically illustrate possible configurations of locking arrangements of the invention,

Figure 8 is a side view of an arrangement for preventing too early operation of the locking elements; and

Figure 9 is an end view of the arrangement of Figure 8.

Referring to the drawings and more particularly to Figure 1 which as stated schematically illustrates a fragmentary portion of a door 1 and its associated door frame 1A, the portion shown being a bottom region 2 of the door 1 , the door region shown including a portion of a vertical side 3 and a portion of a bottom edge 4 is illustrated.

A locking arrangement involving the concepts of the invention is indicated at 5, the arrangement including a rectangular back plate 6 which is secured to the bottom corner of the door by screws or the like 7. A U-shaped channel menber 8 is mounted to the back plate. The channel member can be separately attached to the back plate 6 by welding, by additional screws (not shown) or by the screws 7 additionally securing both the back plate and the channel member to the door 1.

The back plate 6 is such that it can be positionally adjusted with respect to the actual bottom edge A of the door so as to be able to accommodate manufacturing and installation tolerances ^' in the level of the bottom of the door above the floor/ground 17 in the vicinity of the door.

The two limbs 9 and 10 of the channel member 8 are provided with through bores 11 and 12 respectively, these bores being engaged by a locking bolt 13 which is of such length as to project outwardly of both the upper and lower limbs 9 and 10 of the channel member.

The lower projecting end 14 of the bolt 13 is intended to engage with a bore 15 provided in a locking plate 16 located therebeneath and securely held in position on the adjacent floor 17 by any suitable attachment means such as screws 18, the floor being provided with a suitable hole to receive that part of the bolt end that projects through the locking plate 16. The locking plate 16 is so set with respect to the closed position of the bottom corner region 1 of the door 2 that when the door 2 is in its fully closed position the bottom end 14 of the bolt 13 is able to engage into the bore 15 thereby effectively locking the bottom 1 of the door 2 against displacement.

It should be noted that an important aspect of the positional adjustability of the back plate 6 is to ensure that the channel member 8 can be correctly set with respect to the locking plate 16 to ensure correct engagement of the bolt end 14. In addition, the setting of the back plate 6 has an additional function of making matters difficult for a would be intruder to gain access to the bolt 13 by cutting tools or the like.

The bolt 13 is resiliently loaded towards its locking position by a spring 19 located between the inner face of the upper limb 9 and a spring retaining pin 20 transversely engaging in the bolt 13, located within the limbs of the channel member 8.

The upper end 21 of the bolt 13 connects with an operating linkage shown in the Figure 1 as a wire 22. - B-

The upper end of the wire 22 is connected to an L-shaped plate 23 pivotally mounted by way of a pivot 24 to a bracket 25 secured to the door by, for example, screws 26 at a location vertically above the rectangular back plate 6 and thus the bolt 13.

An arcuate slot 27 is provided in the plate 23, the slot being engaged by a pin 28 outstanding from the bracket.

The pin and slot combination 28,27 limits the extent of relative movement between the plate 23 and the bracket 24.

A control rod or other convenient means 29 connects with the plate 23 in such position (in the Figure the position chosen is shown to be at the corner of the plate 23 immediately above the pivot 24) that on exerting pull on the control means 29 the latter is able to displace the plate relative to the bracket 25. The pivotal connection between the plate 23 and the bracket 25 is such that on pivoting the plate 23 clockwise (as seen from the left hand side of the drawing) by exerting said pull on the control means the wire 22 is pulled upwardly and in so doing pulls the bolt 13 upwards to such extent that the lower end 14 thereof disengages from the bore 15 in the locking plate 16.

Once the bolt 13 has been disengaged from the bore 15 the corner 1 of the door 2 is released so that the door can be moved. It will be understood that upon closing the door so that the bolt 13 lines up with the locking plate bore 15, and upon releasing said pull the resilient loading of the spring 19 will automatically drive the bolt 13 into engagement with the locking plate bore 15.

The Figure 1 illustrates the locking arrangement 5 when in the door locking setting and Figure 2 illustrates the locking arrangement when in the door unlocked setting.

Whilst the above discussion has illustrated the locking arrangement as being located adjacent to a side of the door, the locking arrangement could be positioned where ever considered appropriate, for example, centrally of the door .

Referring now to Figure 3, this Figure illustrates the application of the concepts of the invention to the locking of both the upper and lower corner regions of the door 2.

In this arrangement shown in Figure 3 the two locking arrangements are each of a construction similar to that discussed in relation to Figures 1 and 2. In the circumstances it is considered that a detailed discussion of the two locking arrangements included in Figure 3 is not required except to note that the respective components of the lower and upper locking arrangements have been separately identified by the suffixes A and B respectively.

In the arrangement of Figure 3 the two locking arrangements 5A and 5B are respectively connected by way of connecting linkages 22A and 22B to the opposite ends 30 and 31 of a short bar 32 mounted to a rotatable pivot unit 33. In practice, this pivot unit can be associated with a key operated lock mechanism (not shown) and associated turning handle (likewise not shown) provided on the side of the door remote from the side carrying the illustrated locking means .

With this arrangement it will be noted that on turning the operating handle (not shown) so as to rotate the bar 32 clockwise (as seen in the Figure 3) the rotation of the bar exerts upward pull on the locking bolt 13B and downward pull on the locking bolt 13A thereby causing the bolts 13A - 1 Q-

and 13B to disengage from their respective locking plates 16A and 16B thereby to free the door from its locked condition .

When it is desired to cause the bolts 13A and 13B to engage with their associated locking plates 16A and 16B the operating handle, and thus the bar 32 is rotated in the opposite sense. On rotation of the bar 32 in this opposite sense the opening pull on the linkages 22A and 22B is released whereby the resilient loading of the associated springs 19A and 19B will allow the bolts 13A and 13B automatically to re-engage their associated locking plates as soon as the door has been returned to its closed position .

It will be appreciated that an arrangement such as is shown in Figure 3 would be located adjacent each side of the door .

Where it is not desired to involve two separate operating handles but to rely upon a single operating handle, the latter would by located centrally of the width of the door whose opening is to be controlled.

Thus where it is required to provide for a operating handle located centrally of the width of the door and additionally to be able to control the operation of four locking arrangements the operating handle and its associated pivot 33 carrying the bar 32 would be thus located and operationally connected to means for enabling the simultaneously operation of the four locking arrangements located, for example, one to each corner of a door.

A first embodiment of such an installation is shown in Figure 4. Referring now to Figure 4 this Figure illustrates the lower and upper locking arrangements provided adjacent to one vertical side of a door. A similar in construction, arrangement of two further locking arrangements (not shown) would be similarly located adjacent to the other vertical side of the door. In practice, all four of these locking arrangements would be of the same construction as those shown in and thus have the same reference numerals.

In addition to these two loc ing means two further similar lower and upper locking arrangements (not shown) are provided at the other side of the door. For convenience when it is required to refer to the locking arrangements 5 individually in relation to a particular side of a door, they will be identified with reference to the left or right hand side of the door as shown in the Figures.

The four locking ar rangememnts are simultaneously controlled from a central pivot unit 32 and associated bar 32.

The two locking arrangements 5A, 5B provided at the right hand side of the door and the associated drum/pulley, and connection cable linkages 22A and 22B are in the mechanical sense identical to those provided for the left hand side of the door. Since a detailed description of the right hand side locking arrangements and their associated linkages and pulley would be essentially identical to that associated with the left hand side of the door, only the locking arrangements at the left hand side of the door will be described in detail.

Thus in the embodiment of Figure 4 a pulley arrangement 34 is provided mid-way between the lower and upper locking arrangements 5A and 5B, the pulley arrangement 34 being secured to the door by, for example, screws 35. A similar pulley (not shown) is provided for the right hand side of the door other two locking means.

In the embodiment of Figure 4 the cable linkages 22A and 22B are engaged with the pulley arrangement 34 as shown in such matter that both of the linkages 22A and 22B following

their engagement with the pulley 34 connect with the end 30 of the bar 32 so that any pull exerted upon the linkages 22A and 22B as a result of the rotation of the bar 32 by the pivot unit (by way of the operating handle, not shown) produces oppositely directed pull on the locking bolts 13A and 13B.

In a similar manner the two linkages 22C and 22D associated with the two right hand side of the door locking arrangements and associated drum/pulley arrangement (not shown) connect with the end 31 of the bar 32 and are thus able simultaneously to exert pull on their two associated locking bolts (not shown).

Referring now to Figure 5 this illustrates a variation of the arrangement shown in Figure 4. In the Figure 5 variation the locking arrangements 5A,5B, etc., are as shown and described in relation to the previous Figures.

The essential differences between the Figure 4 and 5 installations/systems is that the operating arrangement for the locking means 5A,5B, etc., is similar to that specifically discussed in relation to Figures 1 and 2 (components 23,24,25,28 and 29); and that the installation of Figure 5 includes a drum/pulley arrangement 36 additional to the two drum/pulley arrangements 34 provided in the Figure 4 installation.

The pairs of linkages 22A,22B and 22C,22D are combined to provide two common linkages 22E and 22F. These common linkages 22E and 22F wrap with this additional drum/pulley arrangement 36 prior to these linkages being connected to the pivoted plate 23. In other words the four linkages 22A,22B,22C, and 22D are effectively connected by way of the pulleys 34 and 36 to the pivoted plate 23.

The winding relationship with the additional drum/pulley 36 is such that upon exerting pull on the member 29 the four linkages 22A,22B, 22C and 22D are simultaneously caused to exert pull on their respective locking bolts 13A, 13B etc.

Referring now to Figures 6A to 6D, these Figures schematically illustrate a secondary form of locking arrangement which is intended to be used in conjunction with the locking arrangements previously discussed.

Basically, the secondary locking arrangement involves providing on the door frame adjacent to a locking arrangement 5, 5A, 5B etc., a pin carrying element which is intended to be engaged by a further plate mounted to the door at a location adjacent to the associated locking arrangement 5. It is intended that the direction of the engagement between the further plate and its associated pin should be transverse to the direction of engagement of a bolt 13 with its locking plate. It has been found that by providing such additional plate and locking pin combination that any attempt to lever open the bolts 13 from their locking plates 16 is substantially further restricted .

Thus, as shown in Figure 6A a bracket 40 includes a first part 41 having bores .42 by means of which screws (not shown) can secure the bracket to the inner face of a door, a stepped part 43, and a third part 44 extending parallel to the part 41. This third part is provided with a pin receiving bore 45. Figure 6B is a perspective view of a pin carrying bracket 46 including a first part 47 having bores 48 by means of which screws (not shown) can secure the bracket to an inner face of a door frame, a stepped part 49, and a third part 50 on to which is mounted a pin 51, the pin extending towards the plane containing the first part 47.

Figure 6C is a cross-sectional plan view of a door and associated upright of a door frame, the Figure illustrating the manner of mounting the brackets 40, and 46 to a bottom corner of a door and an adjacent part of a door frame respectively .

In practice, the two brackets are mounted as close as possible to the bottom of the inner face of a door and adjacent to an inner vertical edge of the frame. With this arrangement as the door moves to its closure position the bracket part 44 moves towards the bracket part 50 and thus the pin 51 and in so doing the pin 51 is able to engage in the bore 45 provided in the bracket part 40. It will be noted that the direction of engagement of the pin 51 within the bore 45 is transverse (at right angles) to the locking direction of the adjacent bolt 13 of the adjacent locking arrangement 5. The positioning of the two brackets 40 and 46 substantially reduces if not eliminates any possiblity of springing the bolt 13 away from its locking plate 16 when in the locked position. It will also be noted that the pin 51 automatically disengages from the bore 45 upon opening the door following release of the bolt 13.

Referring now to Figures. 7A to 7E each one of those Figures schematically illustrates a configuration of locking arrangements and associated linkages.

In the Figures each one of the arrow heads represents a locking arrangement 5. Thus Figure 7A illustrates the use of two centrally positioned locking arrangements. Figure 7B one upper central and two lower sideways acting lower corner located arrangements. Figure 7C illustrates the provision of two sideways acting lower corner arrangements together with and upper and lower centrally located arrangements. Figure 7D illustrates a relatively complex system including vertically acting upper and lower arrangements at each side of the door and an upper central arrangement, and Figure 7E illustrates greater complexity with the provision of upper and lower vertically acting corner arrangements together with lower sideways acting lower corner arrangements.

It will be appreciated that the linkages of the various locking devices indicated in the systems of locking arrangements 5 shown in Figures 7A to 7E would be intercoupled to a common door operator.

Referring now to Figures 8 and 9 these Figures relate to a modified construction of the fixed and pivoted plates associated with the common operator arrangement for the locking arrangements.

As is shown in these Figures a plate 55 is pivoted by a pivot 24 to a fixed plate 56. The lower end 56 of the plate 55 lies at right angles to the remainder of the plate 55 to provide a lower anchorage 57 for a torsion spring 58. An anchorage 59 for the upper end 60 of the spring 58 is provided on the fixed plate 56.

The pivoted plate 55 is also provided with an anchorage 61 to which any linkages 22 associated with a door installation are connected.

The upper end of 60 of the pivoted plate 55 is provided with an abutment nose 62 which cooperates with the fixed plate 56.

As may be noted from the Figure the action of the spring is automatically to displace the pivoted plate 55 anticlock ise as seen in the Figure 8, and thereby to a position in which pull is not exerted upon any linkages 22 that may be coupled to to a linkage anchorage point 63 provided upon the pivoted plate 55. An aperture 64 which serves as the connection point for any operator arrangement (such as the element 29 used in previous Figures) is provided at the upper end of the pivoted plate 55.

When it is required to operate the locking arrangements 5 involved, that is release, the locking effect produced by the locking arrangements 5 associated with a door, pull is exerted upon the pivoted plate 55 so as to cause the latter to rotation in a clockwise direction as seen in the Figure 8 and thus against the action of the spring 58 into the position shown in chain dotted lines.

As will be appreciated this movement has the effect of causing the locking arrangements 5 to be moved to their door release positions, in which the various locking bolts 13 are withdrawn from the associated locking plates 16.

The relative positioning of the spring anchorages 57,59 with respect to the pivot 24 in conjunction with the position of the abutment nose 59 relative to the pivot 24, and the location of the linkage anchorage 64 relative to the pivot 24 are chosen and inter-related such that whilst a door is in motion and before it has completely engaged with its frame during operation of the door the bolts 13 do not project outwardly of the associated region of the door.

With this arrangement in cases where the locking arrangments 5 are such that the locking bolts 13 thereof move horizontally, i,e, in a sideways direction relative to the door, the bolts cannot foul the door frame and thus prevent the full nesting of the door into its fully closed position with respect to the associated frame.

As has beem indicated several locking arrangements can be provided upon a door. In order to facilitate the operational inter-connections of the associated linkages 22, the bar 32 as shown in the various Figures can be replaced by a plate preferably circular (not shown) which is rotatable about the same pivot axis as that of the bar 32 and which is provided around its periphery with attachment holes or the like for enabling several linkages 22 to be connected to the plate so that a rotation of the plate exerts the requisite opening pull on the various linkages. In a specific plate construction the linkage attachment holes were angularly spaced around the plate at 45 degrees intervals.

Whilst the forgoing has been specifically related to manual operation it will be appreciated that the displacement of the linkages for the purposes of actuating the locking arrangements can be electric motor control thereby allowing for remote operation of the doors.

Claims

1 A door locking system for a vertically hung door (2) characterised by at least two elongate axially displaceable locking elements (13) mounted to the door (1) and separately resiliently loaded towards their door locking engagement with positionally fixed locking elements (16), locking elements operator means (23-29; 55-64) adapted for manual or remote operation, and means (22) for operationally coupling the locking elements with said operator means, the arrangement being such that actution of the operator means causes simultaneous operation of the displaceable locking elements (13) against the resilient loading thereof when it is required to unlock the door and to allow the movable elements (13) separately to engage their associated fixed locking elements when the door is in its closed lockable position.

2. A door locking system as claimed in claim 1, and characterised in that the movable locking elements (13) comprise bolt members adapted to engage with positionally fixed locking plates (16) at positions located centrally of the width of the door (1) and adjacent the top and bottom of the door(4A,4B), and in that the operator means (23-29,55-64) is coupled for operational purposes with the locking bolts (13) by way of flexible linkages (22), one for each bolt.

3. A door locking system as claimed in claim 2, and characterised in that a bolt member (13) is located adjacent the sides of the door (1) in the vicinity of the lower corners of the door, wherein the fixed locking plates (16) are provided in the adjacent floor or lower door frame element, and in that the operator means (23-29,55-64) is coupled for operational purposes with the locking bolts (16) by way of flexible linkages (22), one for each bolt member .

4. A door locking system as claimed in claim 2, and characterided in that a first bolt member (13) is located centrally of the width of the door (1) and adjacent the top (4B) of the door and a further bolt member (13) is located centrally of the door adjacent the bottom (4A) of the door, the associated fixed locking locking plates (16A, 16B)) being correspondingly located, and wherein the operator means (23-29, 55-64) )is coupled for operational purposes with the movable locking bolts by way of flexible linkages (22A,22B), one for each bolt member.

5. A door locking system as claimed in claim 2, and characterised in that a first bolt member (13) is located centrally of the width of the door (1) and adjacent the top (4B) of the door and two further bolt members (13) are located adjacent the sides of the door and in the vicinity of the lower corners of the door, and in that the operator means (25-29; 55-64) is coupled for operational purposes with all of the locking bolts by way of flexible linkages (22), one for each bolt member.

6. A door locking system as claimed in claim 2, and characterised in that bolt members (13) are located centrally of the width of the door (1) and adjacent the top and bottom (A,4B) of the door and two further bolt members are located adjacent the sides of the door and in the vicinity of the lower corners of the door, and in that the operator means (25-29; 55-64) is coupled for operational purposes with the locking bolts by way of flexible linkages (22), one for each bolt member.

7 A door locking system as claimed in claim 2, and characterised in that a first bolt member (13) is located centrally of the width of the door (1) and adjacent the top (4B) of the door, two second bolt members (13) are located adjacent the sides of the door and in the vicinity of the upper corners of the door, in that two third bolt members (13) are located adacent the sides of the door and in the vicinity of the lower corners of the door, and in that the operator means (25-29; 55-64) is coupled for operational purposes with the locking bolts by way of flexible linkages (22), one for each bolt member.

8. A door locking system as claimed in claim 2, and characterised in that two first bolt members (13) are located adjacent the sides of the door and in the vicinity of both the upper and lower corners (4B) of the door, and two further bolt members are located adacent the sides of the door and in the vicinity of the lower corners (4B) of the door, and in that the operator means (2529) is coupled for operational purposes with the locking bolts (13) by way of flexible linkages (22), one for each bolt member.

9. A door locking system as claimed in any one of claims 1 to 8, and chatacterised in that the movable locking member (13) is mounted in a bracket assembly (8) adapted for connection to the door, the bracket member (8) including a back plate (6) and upper and lower outwardly projecting parts serving as guides for the bolt member (13), and in that the resilient loading of the bolt member comprises spring means (19) provided on that part of the bolt member located between the projecting parts.

10. A door locking system as claimed in any one of claim 1 , and characterised in that each movable locking .member (13) is operationally coupled by its associated linkage (22) to a linkage connection element (32) associated with pivot means (33), the arrangement being such that in order to unlock the door (1) following release of the locking mechanism the pivot (33) is turned in the appropriate sense to cause each linkage (22) to withdraw against the resilient loading (19) thereof its associated locking member (13) from its associated fixed locking member (16), thereby to free the door for opening.

11 A door locking system as claimed in claim 10, and characterised in that when two movable locking elements (13) are involved the linkage connection element (32) comprises a bar, to which the linkages directly couple.

12. A door locking system as claimed in claims 10 and 11, and characterised in that a key operable lock mechanism is associated with the door operator means.

13. A door locking system as claimed in claim 10, and characterised in that wherein when more than two movable locking elements (13) are involved, rotatable linkage guide drum means (34) are provided to facilitate the routing of the linkages (22) to the linkage connection element.

14. A door locking system as claimed in claim 10, and characterised in that when several movable locking elements (13) are involved the linkage connection element is arranged to provide provide a separate connection point for each linkage.

15. A door locking system as claimed in any one of claims 1 to 14, and characterised by secondary door locking means (40-51).

16. A door locking system as claimed in claim 14, and characterised in that the secondary locking door locking means (40-51) includes a bolt like member (51) extending transver^se to the di^ction of action of any adjacent movable locking element (13) and adapted to engage with a bore (45) in a fixed member (40-45), the arrangement being such that upon closure of the door, the secondary locking means bolt like member (51) automatically engages with its associated bore (45) in the fixed member as soon as the door attains its closed position.

17. A door locking system as claimed in any one of the preceding claims, and characterised in that the door operator includes means (55-64) for ensuring that the door (1) reaches its fully closed position prior to the release of any one of the movable locking elements towards its locking position.

18. A door locking system as claimed in claim 17, and characterised in that the ensuring means includes a resiliently loaded cam element (55-64)) to which the linkages are operationally connected for the purposes of their operation, the cam being resiliently loaded in a direction such as to resist the resilient loading of the individual movable locking members (13) until the door attains its fully closed position.