GB2504264A

GB2504264A - Latch releasing mechanism

Info

Publication number: GB2504264A
Application number: GB201211631A
Authority: GB
Inventors: Stuart Leslie Norcott
Original assignee: Assa Abloy Ltd
Current assignee: Assa Abloy Ltd
Priority date: 2012-06-29
Filing date: 2012-06-29
Publication date: 2014-01-29
Also published as: GB201211631D0

Abstract

A mechanism for releasing one or more latches on a door in response to actuation of an activation device 2, e.g. a push bar, comprises a casing 22, an activation member 20 mounted in the casing and arranged to rotate from a first position to a second position upon actuation, and a mechanism for converting rotation of the activation member 20 into longitudinal movement of a locking rod assembly 8. The locking rod assembly comprises an elongate locking rod member with a remote bolt end which is in a latching position when the activation member 20 is in its first position and a retracted position when the activation member 20 is in its second position. An end portion of the locking rod assembly 8 closest to the casing is of adjustable length. Also claimed is a latch releasing mechanism comprising a mechanism that moves an output member (locking rod) from a first to a second position in response to movement of the activation member in either direction or a further position in the first direction i.e. from a first to a second or third position. The latch is preferably used on a fire door, panic door or emergency exit.

Description

Latch releasing mechanism This invention relates to a mechanism for releasing one or more latohes on a door in response to pressing of an activation bar or some other activation device, for example a conventional handle. The invention is particularly concerned with what are known as "panic" latching arrangements.

Tt is well known to provide a panic latching arrangement on a door, to allow people to open the door by pressing on an activation bar mounted across the inside of the door. The door may be latched in a closed position by looking rods extending vertically from the region of the activation bar to the top and bottom of the door and/or by a latching bolt extending sideways into a door frame at approximately the same height as the activation bar. A mechanism is required to cause the pressing of the bar to release the locking rods and/or latching bolt.

Such mechanisms have taken a variety of forms in the past. Generally they have been of relatively complex desIgn involving the connection of various assemblies in series and involving a large number of parts. A consequence has been that such arrangements have been expensive to manufacture and prone to failure or breakage, which is of course of particular significance in a mechanism of this kind.

Fitting of such mechanisms can cften be particularly awkward and time consuming. The mechanisms are generally required to be able to operate on different sizes of door and some final adjustment of the length cf a locking rod assembly is therefore required. In a oommon arrangement a locking rod assembly is generally of circular cross-section but carries a sguare cross-section bolt at its distal end, the bolt being screwed into the end of the circular cross-section part and being able to be screwed in or out to adjust its position. Once mounted on a door, however, the square cross-section part becomes non-rotatable so adjustment has to be carried out before fitting to a door.

That can result in more than one fitting of the assembly to the door, making the fitting unduly time-consuming.

It is an object of the invention to provide a latch releasing mechanism that offers an improvement in one or more respects over existing designs.

According to a first aspect of the invention there is provided a mechanism for releasing one or more latches on a door in response to actuation of an activation device, the mechanism comprising: a casing having a front, back, opposite ends and opposite sides, an activation member rotatably mounted in the casing and arranged to rotate from a first position to a second position, upon actuation of the activation device, a mechanism in the casing for converting rotation of the activation member into longitudinal movement of a looking rod assembly, the locking rod assembly oomprising an elongate locking rod member extending from the region of the casing to a remote end for providing a bolt which is in an extended, latching position when the activation member is in its first position and in a retracted, released position when the activation member is in its second position, wherein an end portion of the locking rod assembly in the region of the casing is of adjustable length to adjust the overall length of the locking rod assembly.

By providing a locking rod whose length can be adjusted in the region of the casing, the adjustment can be much simpler for an installer.

The end portion may be positioned outside, or partially or wholly inside, the casing. In an embodiment of the invention described below, the end portion is partly inside and partly outside the casing.

The end portion of the locking rod assembly preferably comprises a pair of telescopically engaging screw threaded members. In an embodiment of the invention described below the locking rod member is an internally screw threaded member of the telescopically engaging screw threaded members, but it should be understood that it may alternatively be externally screw threaded. The end member may be rotatably mounted on the output member of the mechanism in the casing for rotaticn about a longitudinal axis of the end member and may comprise one of the pair of telesccpicaily engaging screw threaded members. Such an arrangement facilitates the adjustment of the length of the locking rod assembly.

The locking rod member is preferably of circular cross-section along all of its length.

A locking arrangement may be provided for locking the telescopically engaging members in a selected position relative to one another. The locking arrangement may take various forms. In a preferred arrangement, the end portion of the locking rod assembly further comprises a locking nut for locking the telescopically engaging members in a selected position relative to one another.

The mechanism may further comprise a further locking rod assembly, the locking rod assemblies extending from opposite ends of the casing. The further looking rod assembly may be of substantially the same design as the first-mentioned looking rod assembly.

The looking rod assembly preferably comprises, in the region of its end opposite the end portion of adjustable length, a datum point for contacting a reference face on a door frame. By providing such a datum point (which may be pointed or a flat, or other shaped, face) adjustment of the length of the locking rod assembly in the region of the casing to the desired length is facilitated.

The locking rod assembly may further comprise a pivotably mounted latching member for latching the locking rod in a retracted, released position. A trip arrangement may be provided, partly on a door frame and partly on the looking rod assembly and the door for releasing the pivotably mounted latching member when the door is closed.

According to the first aspect of the invention, there is also provided a method of installing a mechanism for releasing one or more latches on a door, the method including the steps of providing a mechanism as defined above, fixing the casing to a door and adjusting the length of the end portion of the locking rod assembly, the adjustment being carried out in the region of the casing.

The locking rod assembly may extend substantially vertically away from the casing.

A further locking rod assembly is preferably provided, the locking rod assemblies extending vertically away from the casing in opposite directions, and the method preferably includes the steps of adjusting the lengths of both assemblies, both adjustments being carried out in the regIon of the casing.

According to a second aspect of the invention there is provided a mechanism for releasing one or more latches on a door in response to actuation of an activation device, the mechanism comprising: a casing having a front, back, opposite ends and opposite sides, an activation member rotatably mounted in the casing and arranged to rotate in a first direotion from a first position to a second position, upon actuation of the activation devioe, the member also being mounted for rotation from the first position in a seoond direotion, opposite to the first direction, to a third position, a mechanism in the casing for moving an output member from a first position to a second position for releasing said one or more latches, wherein the mechanism is arranged such that the output member moves from the first position to the second position both when the activation member moves from the first position to the second position and also when the activation member moves from the first position to the third position.

By providing a mechanism as described above, a simple, reliable and economical mechanism with relatively few parts can be provided. As will become clear from further description below, the same mechanism can be adapted for operating a single latching member that moves sideways to engage in a door frame, and/or or it can be adapted for operating one or two vertical locking rods. Furthermore, a mechanism of this kind can readily be arranged to be able to operate when mounted on either side of a door (right handed or left handed) . Since the same components are used for both right handed and left handed versions of the mechanism, the total number of components can be reduced.

In a preferred arrangement the mechanism in the casing comprises a first slide member mounted for sliding movement in an end-to-end direction in the casing and slidable from a first position to a second position, the activation member being coupled to the first slide member such that when the activation member is rotated from its first position to its second position the first slide member is driven from its first position to its second position.

Also in the preferred arrangement, the first slide member is slidabie from a first position to a third position, the sliding movement being in the opposite direction to the direction of sliding from its first position to its second position, the activation member being coupled to the first slide member such that when the activation member is rotated from its first position to its third position the first slide member is driven from its first position to its third position.

Also, in a preferred arrangement the mechanism in the casing comprises a second slide member mounted for sliding movement in a side-to-side direction in the casing and slidable from a first position to a second position, the first slide member being coupled to the second slide member such that when the first slide member is driven from its first position to its second position the second slide member is driven from its first position to its second position. Also in that preferred arrangement, the first slide member is coupled to the second slide member such that when the first slide member is driven from its first position to its third position the second slide member is driven from its first position to its seoond position.

The first and second slide members are preferably of generally lameilar form having front and rear faces, and are arranged in the casing with a rear face of the first slide member adjacent to a front face of the second slide member. The term "generally lameilar" is used in this specification in a very broad sense in respect of a member which has a dimension in one direction which is generally substantially less than the dimensions in two orthogonal directions. It is, however, within the scope of the invention for there to be one or more minor portions of a "generally lamellar" member which do have a dimension in said one direction which is greater than a dimension in an orthogonal direction.

The activation member is preferably positioned in front of the front face of the first slide member and has an activating portion that extends rearwardly from the axis of rotation of the activation member for driving engagement with the first slide member. The activation portion preferably engages the first slide member via a post and slot connection; the activation portion may comprise a U-shaped portion defining an open-ended slot and a post may be received in the slot. Such a coupling is able to transmit rotational movement of the activation member from a middle, first, position in each of its opposite directions of rotation into sliding movement of the first slide member in respective oppcsite directions from a middle, first, position.

The first slide member is preferably mounted for sliding movement in the casing by posts mounted on the first slide member engaging slots on side walls of the casing.

The coupling between the first slide member and the second slide member preferably comprises a camming engagement of inclined faces of the first and second slide members. The inclined faces are preferably inclined at about 45 degrees to the direction of sliding of the first slide member. Preferably there are two pairs of inclined faces and preferably each pair is inclined at about 45 degrees to the direction of sliding of the first slide member and the two pairs of inclined faces are at inclinations of about 90 degrees to one another. In that case movement of the first slide member from a middle, first, position in either of two opposite directions may cause sliding movement of the second slide member in the same first direction from its first position to its second position and movement back to the middle, first, position in either of two opposite directions may cause sliding movement of the second slide member in a second direction opposite to the first direction from its second position to its first position. Such a coupling is able to transmit rotational movement of the activation member from its -10 -middle, first, position in eaoh of its opposite directions of rotation into the same sliding movement of the second slide member from its first position to its second position.

The mechanism preferably further oomprises a latching member mounted on the second slide member, the latching member being in an extended, latching position when the second slide member is in its first position and being in a retracted, released position when the second slide member is in its second position. The latching member may be a chamfered latching member.

Preferably, the mechanism further comprises third and fourth slide members, each mounted for sliding movement in an end-to-end direction in the casing and slidable from a first position to a second position, the third and fourth slide members being connectible to respective locking rods extending from respective ends of the casing, the second slide member being coupled to the third and fourth slide members such that when the second slide member is driven from its first position to its second position the third and fourth slide members are driven from their first positions to their second positions for drawing respective locking rods towards the casing. With such slide members, an especially compact mechanism for providing all the required driving of latches for a variety of applications can be provided. It should be understood that, whilst the third and fourth slide members are described as connectible -11 -to locking rods, that does not mean that locking rods are necessarily present. The presence of the locking rods will be determined according to the application in which the mechanism is emplcyed. Furthermcre, if locking rcds are not provided, a further possibility is to omit the third and fourth slide members. Accordingly, it is preferred that the mechanism is operable both with the third and fourth slide members in the casing and with the third and fourth slide members omitted from the casing.

Preferably the third and fourth slide members are of generally lamellar form having front and rear faces, and are arranged in the casing with a rear face of the second slide member adjacent to front faces of the third and fourth slide members. !Jjhe third and fourth slide members may be provided with forwardly projecting portions at their remote ends, the locking rods being connectible to the forwardly projecting portions.

Preferably the third and fourth slide members are mounted in the casing for movement in substantially the same plane and move towards each other as they move from their first positions to their second positions.

Preferably the coupling between the second slide member and each of the third and fourth slide members comprises a post on one member slidably located in an inclined slot in the other member. In an embodiment of the invention described below, posts are provided on the second slide member and inclined slots are provided in the third -12 -and fourth slide members. The posts may be separate parts located in respective bores in oppcsite end pcrticns of the second slide member.

The mechanism may further comprise a locking rod assembly ccnnected to the third slide member. The locking rod assembly preferably comprises an elongate locking rod member extending from the region of the casing to a remote end for providing a bolt which is in an extended, latching position when the third slide member is in its first position and in a retracted, released position when the third slide member is in its second position. An end portion cf the locking rod assembly in the regicn of the casing may be of adjustable length to adjust the overall length of the locking rod assembly. !I!he end portion may be positioned outside, or partially or wholly inside, the casing. In an embodiment of the invention described below, the end portion is partly inside and partly outside the casing.

The end portion of the locking rod assembly comprises a pair of telescopically engaging screw threaded members.

In an embodiment of the invention described below, an externally screw threaded end member is mounted on the third slide member and an internally screw threaded locking rod engages the end member and extends away from the casing; it should be understood, however, that the external and internal threads could alternatively be provided on the other ones of the pair of members. The end member is -13 -preferably rotatably mounted on the third member for rotation about its longitudinal axis. Such an arrangement facilitates the adjustment of the length of the locking rod assembly. In partioular it allows the adjustment to be carried out in the region of the casing rather than at the remote ends of the locking rods.

The mechanism may further comprise a further locking rod assembly connected to the fourth slide member. The further locking rod assembly may be of substantially the same design as the first-mentioned locking rod assembly.

The locking rod assembly preferably comprises, in the region of its end opposite the end portion of adjustable length, a datum point for contacting a reference face on a door frame. By providing such a datum point (which may be pointed or a flat, or other shaped, face) adjustment of the length of the looking rod assembly in the region of the casing to the desired length is facilitated.

The looking rod assembly may further comprise a pivotably mounted latching member for latching the locking rod in a retracted, released position. A trip arrangement -14 -may be provided, partly on a door frame and partly on the locking rod assembly and the dcor for releasing the pivotably mounted latching member when the door is closed.

The mechanism may further ccmprise a latch operating member rotatably mounted in the casing for engagement by a handle assembly, the latch operating member having first and second positions and being coupled to the second slide member such that rotation of the latch operating member from its first position to its second position drives the second slide member from its first position to its second position. The latch operating member may be arranged for engagement by an external actuator, for example, a handle assembly mounted on an opposite side of a door to the mechanism.

The mechanism preferably further comprises resilient means for resiliently biasing the mechanism into a condition where the first and second slide members are in their first positions. The second slide member is preferably resiliently biased into its first position.

Preferably the resilient bias is provided by one or more compression springs. In an embodiment of the invention the resilient bias is provided by a pair of compression springs. By biasing the second slide member into its first position other parts of the mechanism can be biased into their corresponding positions. In particular the first slide member and/or the activation member and/or the third and fourth slide members may be biased into their first -15 -positions indirectly by the biasing of the second slide member into its second position. The biasing of the second slide member may also bias the latch operating member into its first position.

The mechanism may further comprise an activation device, which may be an activation bar, for mounting on a door with one end of the bar connected to the activation member. When said one end of the bar is mounted on the door, the other end of the bar may be mounted on the door for movement in synchronism with said one end of the bar.

Said other end of the bar is preferably connected to a rotatable member rotatably mounted in a further casing.

The further casing may be formed from the same component(s) as the casing at said one end of the bar. !I!hat reduces the number of parts to be stocked.

The invention further provides in the first and second aspects a door assembly comprising a door and a mechanism as defined above mounted on the door. The door may be mounted in a door frame. The door may be held in a closed position by engagement of one or more locking rod assemblies in one or more keeps in the top and/or bottom of the door frame and/or by engagement of a latching member in a keep in a side of the door frame in the region of the casing.

Whilst various aspects of the invention have been described above, it should be understood that, as already implied, features described in one context may also be -16 -provided in another context, even when that is not explicitly stated. In particular features described in respect of the first aspeot of the invention may be empThyed in the second aspect of the invention and vice versa.

By way of example an embodiment of the invention will now be described with reference to the accompanying schematic drawings, of which: Figure 1 is an isometric view of a panic latching arrangement, including a latch releasing mechanism, for mounting on a door; Figure 2 is an isometric view to a larger scale of the latch releasing mechanism; Figure 3 is an exploded view from the front of the latch releasing mechanism; Figure 4a is an isometric view from the rear of parts of the latch releasing mechanism shown in a latched condition, Figure 4b is an isometric view from the rear of parts of the latch releasing mechanism shown in a released condition, Figure Sa is an isometric view from the front of a first slide member of the mechanism, Figure Sb is an isometric view from the rear of the first slide member of the mechanism, Figure 6a is an isometric view from the front and one side of a second slide member of the mechanism, -17 -Figure 6b is an isometric view from the front and an opposite side of the second slide member of the mechanism, Figure Eo is an isometric view from the rear of the second slide member of the mechanism, Figure 7a is an isometric view, similar to Figure 2 but to a larger scale, of a top region of the mechanism, Figure 7b is an isometric view, similar to Figure 2 but to a larger scale, of a bottom region of the mechanism, Figure 8 is a an isometric view, similar to Figure 1 but to a larger scale of a part of the panic latching arrangement, Figure 9a is an isometric view of a trip mechanism provided in the region of the top of the panic latching arrangement, Figure 9b is a view of part of the trip mechanism from the rear, Figure 9c is a sectional view along the lines A-A in Figure 9b, Figure ba is an isometric view of a latch operating member, Figure lOb is a front view of the second slide member in a second retracted position, having been retracted by the latch operating member, -18 -Figure iCc is a front view of the second slide member in a first extended position, prior to having been retracted by the latch operating member, Figure lCd is a side view of the seoond slide member and latch operating member, and Figure 11 is an exploded view from the rear of parts of the latch releasing mechanism without the casing.

Figure 1 shows a latching mechanism 1 configured for use on a door (not shown) . An activation bar 2 is oonnected to and extends horizontally between a master unit 4, comprising a latch releasing mechanism embodying the invention, and an idler unit 6. An upper locking rod 8 is connected to and extends vertically away from the top of the master unit 4 to an upper trip mechanism 10. A lower locking rod 12 is connected to and extends vertically away from the bottom of the master unit 4 and is engageable with a guide 14 mounted, in use, in a floor (not shown) Figure 2 shows the master unit 4 with a cover removed.

The master unit 4 comprises a casing 22 composed of a casIng base 22a coplanar with the surface of the door (not shown) , and two casing sides 22b, 22c mounted on either side of the base 22a and extending in a plane perpendicular to the base and away from the door. The casing 22 has a front (remote from the door) , a back (in contact with the door), opposite ends (top and bottom) and opposite sides.

-19 -The activation bar 2 is fixed to a first link member 18 which is connected in the region of one of the casing sides 22c to an activation member 20, which is rotatably mounted between the casing sides 22b, 22c at the front of the casing. The activation member 20 is detachably connected to the first link member 18 so that pivoting of the first link member 18 causes the activation member 20 to rotate.

A first slide member 24, of a generally lamellar form, is mounted between the casing sides 22b, 22c, behind the activation member 20. The first slide member 24 is mounted to slide up and down vertically (in an end-to-end direction) by two rods 26 which extend across the whole width of the slide member 24, each end of each rod 26 extending through a vertical slot 28 in each casing side 22b, 22c.

Figure 3 shows in an exploded view the components contained within the master unit 4. Here it can be seen that the activation member includes a rearwardly projecting U-shaped portion 29 which defines an open-ended slot in which a rod 33 mounted on the front of the first slide member 32 is received.

Figures 4a and 4b show rear views of the latching mechanism contained within the master unit 4 in the latched and released configurations respectively. Mounted behind the first slide member 24 is a second slide member 30 of a generally lamellar form. A chamfered latching member 16 is -20 -rigidly fixed to the side of the second slide member further from the activation bar 2. The second slide member is mounted for side-to-side movement on two rods 36 of variable cross section which extend through the member 30.

On the opposite side of the second slide member 30 to the latching member 16, two coiled springs 38 surround the two rods 36 and are compressed between the second slide member and the casing side (22b, see Figure 2) Referring also to Figures 5a and 5b, one of two triangular protrusions 40 located at opposite ends of the rear of the first slide member 24 (see Figures 5a and b for a detailed view of the first slide member 24), contacts a triangular wedge 42 centrally located on the front of the second slide member 30 which is shown in Figure 6. ftc triangular protrusions 40 and the triangular wedge 42 define inclined faces that are able to engage one another, as will be described further below, and which are inclined at 45 degrees to the horizontal.

Returning to Figure 4a, mounted for vertical (end-to-end) movement in substantially the same plane behind the second slide member 30 are a third slide member 32 and a fourth slide member 34, both of generally lamellar form.

The third slide member 32 is located above the fourth slide member 34. Two posts 44, 46 are fixed in opposite ends of the second slide member 30, and extend rearwardly from the rear face of the second slide member. One post 44 extends rearwardly with the distal end of the post slidably located -21 -in an inclined slot 48 in the third slide member 32. The other post 34 extends rearwardly with the distal end of the post slidably located in an inolined slot 50 in the fourth slide member 34. The slots 48 and 50 are inolined at 45 degrees to the horizontal.

At each of the top end of the third slide member 32, and the bottom end of the fourth slide member 34, a forwardly projecting part 52, 54 is provided with an open-ended slot extending rearwardly from its front edge.

Figure 7a shows the top region of the master unit 4.

An externally threaded member 58 containing a waisted section 60 extends vertically away from the master unit 4.

The waisted section 60 of the threaded member 58 is located in the slot in the part 52 of the third slide member. The upper locking rod 8 extends vertically upwards away from the master unit 4 and contains an internal thread which telescopically engages the threaded member 58. A locking nut 56 also engages the threaded member 58 between the part 52 and the upper locking rod 8.

Figure 7b shows the bottom region of the master unit 4 which has a similar arrangement. The waisted section 66 of an externally threaded member 64 is located in the slot in the part 54. The threaded member 64 telescopically engages an internal thread of the lower locking rod 12 which extends vertically away from the master unit 4. A locking nut 62 also engages the threaded member 64.

-22 -Figure 8 shows the idler unit 6. The aotivation bar 2 is fixed to a second link member 68 which is detachably mounted on a shaft member 72 rotatably mounted across a casing 70. A torsion spring 74 is mounted on the shaft member 72 so as to resiliently bias that member against rotational movement in either direction from the position shown in Figure 8.

Figure 9a shows a trip mechanism 10. The distal end of the upper looking rod 8 is located in a circular hole in the keep 76, which has a generally flat plate which is attached to a downwardly facing part of a door frame (not shown) . Fixed to the front of, and extending down from, the keep 76 is a trip-tab 78. rhen the door is closed (the state shown in figure 9a) the trip-tab 78 abuts the upper end of a trip-lever 80. The trip-lever 80 is rotatably mounted in a trip-cover 82 with the lower half of the trip-lever being contained within the trip-cover 82 which is fixed to the door (not shown) . A gauge 83 extends vertically upwards from the back edge of the top of the trip-cover 82.

Figure 9b shows an internal view of the trip mechanism inside the trip-cover 82. A torsion spring 86 resiliently biases the trip-lever 80 such that, in the absence of an external force, the lower end of the trip-lever 80 bears against the upper locking rod 8 and, in the position shown in Figure 9c, engages a waisted section 88 on the upper locking rod 8.

-23 -Figures ba to lOd show the structure and operation of a latch operating member 90 which is rotatably mounted on the second slide member 30. The latch operating member 90 has a latch operating lug 90a protruding from the front of the latch operating member 90 and disposed within a v-shaped channel 31 centrally located on the back of the second slide member 30. The latch operating member 90 has a sguare indentation 90b upon its back surface (see Figure lOa) designed to engage with a sguare cross-section shaft of a handle assembly (not shown) mounted on the opposite side of a door from the latching arrangement.

Operation of the mechanism will now be described starting from the usual position into which the parts are resiliently biased (the position shown in figures 1 and 2)

In summary, when the activation bar 2 is pressed

downwardly and inwardly, the bar rotates from a first position to a second position. As a conseguence of this rotation the mechanism contained in the master unit 4 simultaneously causes each of (1) the upper locking rod 8, (ii) the lower locking rod 12 and (iii) the latch member 16 to move from an extended, latching position to a retracted, released position. The upper locking rod 8 is drawn towards the master unit 4 and therefore retracts from keep 76. The lower locking rod 12 is drawn towards the master unit 4 and therefore retracts from the guide 14. The latch member 16 is drawn towards the master unit 4 and therefore disengages from the strike plate (not shown) . Once all -24 -three latches (upper looking rod 8, lower locking rod 12 and latch member 16) are withdrawn the door may be opened.

The movements of the individual parts during this operation will now be desoribed.

Rotation of the activation bar 2 from the first position to the second position causes the first link member 18 to rotate the activation member 20 clockwise as seen in Figure 2 from a first position to a second position.

The first slide member 24 is constrained to move in a vertical (end-to-end) direction. The rotational movement of the activation member 20 is therefore translated into a linear movement of the first slide member 24 by the U-shaped portion 29 and the rod 33. j!hus, when the activation member 20 is rotated from its first position to its second position, the first slide member 24 is driven from a first position to a second position. In the present embodiment the first slide member moves upwards from the first position to the second position.

As a result of the engagement of one of the triangular protrusions 40 on the rear face of the first slide member 24 with the triangular wedge 42 on the front face of the second slide member 30, the second slide member 30 is driven from a first position to a second position. The second slide member 30 is constrained to move in a side-to-side direction. Thus, as the first slide member moves upwards, the second slide member 30 moves towards the -25 -actIvation bar 2. The latch member 16 which is fixed to the second slide member 30 also therefore moves towards the activation bar 2 and is therefore withdrawn into the oasing and out of engagement with a keep or the like on a door frame.

The side-to-side movement of the second slide member causes the posts 44, 46 fixed to the back of that member to slide in the inclined slots 48, 50 on the third and fourth slide members 32, 34. The force generated by the posts 44, 46 on the side of the slots 48, 50 causes each of the third and fourth slide members 32, 34 to move from a first position to & second position. As the third and fourth slide members 32, 34 are constrained to move in the end-to-end direction the movement of the post 44, 46 in the inclined slots 48, 50 causes the third and fourth slide members 32, 34 to move vertically and inwards towards the centre of the casing 22. Figure 4a shows a perspective view of the latching mechanism from behind with the slide members in their first, latched, positions. Figure 4b shows the same view with the slide members in their second, released, positions.

The inward movement of the third and fourth slide members 32, 34 causes the locking rods 8, 12 to be drawn inwards towards the casing. The upper locking rod 8 moves from an extended, latching position to a retracted, released position when the third slide member 32 moves from its first position to its second position.

-26 -As the upper locking rod 8 is drawn inward the remote end of the rod moves away from the keep 76 bringing the waisted section 88 into alignment with the lower end of the trip-lever 80. As the door is opened and pushed outwards the trip-tab 78 no longer abuts the upper end of the trip- lever 80 and the torsion spring 86 acts to rotate the trip-lever 80 such that its lower end engages the waisted section 88 of the upper locking rod 8.

The torsion spring 74 in the idler unit 6 resiliently biases the activation bar 2 towards the first position.

The springs 38 acting on the second slide member 30 also bias that member towards its first position and thereby bias the activation bar 2 towards its first position as a result of the interconnectivity of the various slide members. However, the engagement of the trip-lever 80 with the waisted section 88 of the upper locking rod 8 prevents that rod, and thereby the third slide member 32 from moving. Thus, the trip mechanism 10 acts to hold the latching mechanism in the released configuration whilst the door is open.

When the door is closed the upper end of the trip-lever 80 contacts the trip-tab 78 causing the trip-lever 80 to rotate and disengage from the waisted section 88 of the upper locking rod 8. Thus, the rod 8 and thereby the third slide member 32 are once more free to move and the spring biasing of the idler unit 6 and second slide member 30 acts to return the mechanism to the latched configuration with -27 -all the elements thereof returning to their respective first positions.

In crder for the trip mechanism tc work effectively the trip-tab 78 on the keep 76 which is fitted to the door frame, and the upper end cf the trip-lever 80 which is mounted on the door via the trip-cover 82 must be correctly aligned. The trip-cover 82 is correctly position by using the gauge 83. When correctly installed the end of the gauge 83 contacts the keep 76 thus ensuring the correct spacing between trip-cover 82 and the keep 76.

The length of the upper and lower locking rods 8, 12 is dictated by the geometry of the door to which the latching mechanism is fitted. Consequently there is a requirement for the length of the rods to be adjustable.

This is achieved by the telescopic threading of the upper and lower locking rods 8, 12 onto the corresponding threaded members 64, 58. During installation the master unit 4, trip mechanism 10 and guide 14 are all mounted on the door in the desired position. The upper end of upper locking rod 8 is then inserted into the keep 76 via the trip-cover 82. The externally threaded member 58 is threaded into the internal thread of the upper locking rod 8 and turned until a sufficient proportion of the threaded member 58 is located inside the upper locking rod 8, such that the waisted section 60 of the threaded member 58 is aligned with the part 52 on the third slide member 32. A looking nut 56 is used to lock the upper locking rod 8 and -28 -threaded member 58 in a selected position relative to one another. A similar process is followed in order to adjust the length of the lower locking rod 12 such that the end of that rod is located in the guide 14 when the door is latched.

The door may be opened from outside (the side opposite to that on which the activation bar 2 is installed) . A shaft extends from a handle assembly on the outer side of the door and engages with the sguare indentation 90b on the back of the latch operating member 90. Rotation of the shaft when engaged with the indentation causes the latch operating member 90 to rotate. The latch operating tab 90a is engaged with the v-shaped channel 31 on the back of the second slide member 30. Rotation of the latch operating member 90 causes the latch operating tab BOa to exert a force on a side of the v-shaped channel 31 such that the second slide member 30 is moved from its first position to its second position, that is the second sliding member 30 moves inward towards the activation bar 2. This movement of the second slide member 30 necessarily results in the movement of the latching member 16 and the upper and lower locking rods 8, 12 (via the third and fourth slide members 32, 34) to the retracted, released position. The symmetrical profile of the v-shaped channel 31 results in the second slide member 30 moving from the first position to the second position regardless of the direction in which the latch-operating member 90 is rotated.

-29 -The discussion above is with referenoe to the aotivation bar 2 rotating clockwise from the first position to the second position as a result of downwards pressure on the bar 2. Zs may be understood from the desoription above, the activation bar 2 may also be rotated upwards from a first position to a third position in order to open the door. This anti-clockwise rotation (anti-clockwise as seen in Figures 1 and 2) is transmitted by the first link member 18 to the activation member 20, which rotates from a first position to a third position, the direction of said rotation being opposite to that which takes place when the activation bar 2 is pressed downwards. The motion of activation member 20 is translated via the U-shaped portion 29 and the rod 33 into a downward (as opposed to upward) linear movement of the first slide member 24, from a first position to a third position. In the present embodiment the triangular protrusions 40 on the back of the first slide member 24 are symmetrical, as is the triangular wedge 42 centrally located on the second slide member 30. This symmetry means that although the direction of movement of the first slide member 24 may change according to whether the activation bar 2 has been rotated in a clockwise or anti-clockwise direction, the resulting motion of the second slide member 30 will always be in the same direction (towards the activation bar) . Consequently the iatohing member 16 and upper and lower looking rods 8, 12 are still moved from the extended, latched position to the retracted, -30 -released position regardless of the direotion in which the activation bar is rotated.

The master unit 4 described is shown in Figure 1 mounted on the left hand side of a panic latching arrangement as viewed in Figure 1 with an idler unit 6 mounted on the right hand side, but it will now be seen that the two units can be interchanged without any modification being required to them. This reduces the number of components required for the arrangement and simplifies fitting of the arrangement.

In order to further reduce the number of types of component that must be stored, the same casing may be used in both the master unit 4 and the idler unit 6.

Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. The master unit 4 may, for example, be used without the upper and lower locking rods 8, 12 and the associated trip mechanism and guide 14. No change is needed to the configuration of the master unit 4 in order to achieve this; the locking rods are simply not attached to the third and fourth slide members 32, 34. Similarly the latching member 16 may not be provided in some applications if only one or more vertical locking rods are reguired.

-31 -r7here in the foregoing desoription, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then suoh equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true soope of the present invention, which should be construed so as to encompass any such equivalents. Tt will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims.

Claims

-32 -ClaIms: 1. A mechanism for releasing one or more latches on a door in response to aotuation of an activation devioe, the mechanism comprising: a casing having a front, baok, opposite ends and opposite sides, an activation member rotatably mounted in the casing and arranged to rotate from a first position to a second posItion, upon actuation of the activation device, a mechanism in the casing for converting rotation of the activation member into longitudinal movement of a locking rod assembly, the locking rod assembly comprising an elongate locking rod member extending from the region of the casing to a remote end for providing a bolt which is in an extended, latching position when the activation member is in its first position and in a retracted, released position when the activation member is in its second position, wherein an end portion of the locking rod assembly in the region of the casing is of adjustable length to adjust the overall length of the locking rod assembly.
2. A mechanism according to claim 1, in which the end portion of the locking rod assembly is partly inside and partly outside the oasing.
3. A mechanism according to claim 1 or 2, in which the end portion of the looking rod assembly comprises a pair of telescopically engaging screw threaded members.

-33 -
4. A mechanism acccrding to claim 3, in which the locking rod member is an internally screw threaded member of the telescopically engaging screw threaded members.
5. A mechanism according to claim 3 or 4, in which an end member rotatably mounted on an output member of the mechanism in the casing for rotation about a longitudinal axis of the end member comprises one of the pair of telescopically engaging screw threaded members.
6. A mechanism according to any of claims 3 to 5, in which the end portion of the locking rod assembly further comprises a locking nut for locking the telescopically engaging members in a selected position relative to one another.
7. A mechanism according to any preceding claim, further comprising a further locking rod assembly, the locking rod assemblies extending from opposite ends of the casing.
8. A mechanism according to any preceding claim, in which the locking rod assembly comprises in the region of its end opposite the end portion of adjustable length a datum point for contacting a reference face on a door frame.
9. A mechanism according to any preceding claim, in which the locking rod assembly further comprises a pivotably mounted latching member for latching the locking rod in a retracted, released position.
10. A door assembly comprising a door and a mechanism according to any preceding claim mounted on the door.

-34 -
11. A method of installing a mechanism for releasing one or more latches on a door, the method including the steps of providing a mechanism according to any preceding claim, fixing the casing to a door and adjusting the length of the end portion of the locking rod assembly, the adjustment being carried out in the region of the casing.
12. A method according to claim II, in which the locking rod assembly extends substantially vertically away from the casing.
13. A method according to claim II or 12, in which a further locking rod assembly is provided, the locking rod assemblies extending vertically away from the casing in opposite directions, and the method includes the steps of adjusting the lengths of both assemblies, both adjustments being carried out in the region of the casing.
14. A mechanism for releasing one or more latches on a door in response to actuation of an activation device, the mechanism comprising: a casing having a front, back, opposite ends and opposite sides, an activation member rotatably mounted in the casing and arranged to rotate in a first direction from a first position to a second position, upon actuation of the activation device, the member also being mounted for rotation from the first position in a second direction, opposite to the first direction, to a third position, -35 -a mechanism in the casing for moving an output member from a first position to a second position for releasing said one or more latches, wherein the mechanism in the casing is arranged such that the output member moves from the first position to the second position both when the activation member moves from the first position to the second position and also when the activation member moves from the first position to the third position.
15. A mechanism according to claim 14, in which the mechanism in the casing comprises a first slide member mounted for sliding movement in an end-to-end direction in the casing and slidable from a first position to a secoud position, the activation member being coupled to the first slide member such that when the activation member is rotated from its first position to its second position the first slide member is driven from its first position to its second position.
16. A mechanism according to claim 15, in which the first slide member is slidabie from a first position to a third position, the sliding movement being in the opposite direction to the direction of sliding from its first position to its second position, the activation member being coupled to the first slide member such that when the activation member is rotated from its first position to its third position the first slide member is driven from its first position to its third position.

-36 -
17. A mechanism acccrding to claim 15 or 16, in which the mechanism in the casing ccmprises a second slide member mounted for sliding movement in a side-to-side direction in the casing and slidable from a first position to a second position, the first slide member being coupled to the second slide member such that when the first slide member is driven from its first position to its second position the second slide member is driven from its first position to its second position.
18. A mechanism according to claims 16 and 17, in which the first slide member is coupled to the second slide member such that when the first slide member is driven from its first position to its third position the second slide member is driven from its first position to its second position.
19. A mechanism according to claim 17 or 18, in which the first and second slide members are of generally lamellar form having front and rear faces, and are arranged in the casing with a rear face of the first slide member adjacent to a front face of the second slide member.
20. A mechanism according to claim 19, in which the activation member is positioned in front of the front face of the first slide member and has an activating portion that extends rearwardly from the axis of rotation of the activation member for driving engagement with the first slide member.

-37 -
21. A mechanism acccrding to any of claims 17 to 20, in which the coupling between the first slide member and the second slide member comprises a camming engagement of inclined faces of the first and second slide members.
22. A mechanism according to any cf claims 17 to 21, further comprising a latching member mounted on the second slide member, the latching member being in an extended, latching position when the second slide member is in its first position and being in a retracted, released position when the second slide member is in its second position.
23. A mechanism according to any of claims 17 to 22, in which the mechanism further comprises third and fourth slide members, each mounted for sliding movement in an end-to-end direction in the casing and slidable from a first position to a second position, the third and fourth slide members being connectible to respective locking rods extending from respective ends of the casing, the second slide member being coupled to the third and fourth slide members such that when the second slide member is driven from its first position to its second position the third and fourth slide members are driven from their first positions to their second positions for drawing respective locking rods towards the casing.
24. A mechanism according to claim 23, in which the third and fourth slide members are of generally lamellar form having front and rear faces, and are arranged in the casing -38 -with a rear face of the second slide member adjacent to front faoes of the third and fourth slide members.
25. A mechanism according to claim 23 or 24, in which the third and fourth slide members are mounted in the casing for movement in substantially the same plane and move towards each other as they move from their first positions to their second positions.
26. A mechanism according to any of claims 23 to 25, in which the coupling between the second slide member and each of the third and fourth slide members comprises a post on one member slidably located in an inclined slot in the other member.
27. A mechanism according to claim 26, in which posts are provided on the second slide member and inclined slots are provided in the third and fourth slide members.
28. A mechanism according to any of claims 22 to 27, further comprising a locking rod assembly connected to the third slide member.
29. A mechanism according to claim 28, in which the locking rod assembly comprises an elongate locking rod member extending from the region of the casing to a remote end for providing a bolt which is in an extended, latching position when the third slide member is in its first position and in a retracted, released position when the third slide member is in its second position.
30. A mechanism according to claim 29, in which an end portion of the looking rod assembly in the region of the -39 -casIng is of adjustable length to adjust the overall length of the locking rod assembly.
31. A mechanism according to claim 30, in which the end portion of the locking rod assembly comprises a pair of telescopically engaging screw threaded members.
32. A mechanism according to claim 31, in which the end portion of the looking rod assembly further comprises a locking nut for locking the telescopically engaging members in a selected position relative to one another.
33. A mechanism according to any of claims 30 to 32, in which the locking rod assembly comprises in the region of its end opposite the end portion of adjustable length & datum point for contacting a reference face on a door frame.
34. A mechanism according to any of claims 30 to 33, in which the locking rod assembly further comprises a pivotably mounted latching member for latching the locking rod in a retracted, released position.
35. A mechanism according to any of claims 17 to 34, further comprising a latch operating member rotatably mounted in the casing for engagement by an external actuator, the latch operating member having first and second positions and being coupled to the second slide member such that rotation of the latch operating member from its first position to its second position drives the second slide member from its first position to its second position.

-40 -
36. A mechanism acccrding to any of claims 17 to 35, further comprising resilient means for resiliently biasing the mechanism into a condition where the first and second slide members are in their first pcsitions.
37. A door assembly comprising a door and a mechanism according to any of claims 14 to 36 mounted on the door.