SCOPE OF THE INVENTION

This invention relates to a sliding latch, and in particular to a sliding latch used also as a locking bolt, in particular for securing two movable panels together and/or for securing one movable panel to an fixed frame.

In this specification, "upper" and "lower" and similar geometric terms refer to parts in their normal condition of use, unless otherwise specified in relation to the drawings.

BACKGROUND TO THE INVENTION

Both sliding and hinged panels need on occasions to be made more secure, not only against an unlawful opening movement generally parallel to their plane (as might occur by use of a housebreaker's jemmy) but also against bursting movement by a force perpendicular to their plane (as might occur from a hammer blow against the lock, typically delivered in the panel opening direction by an intruder wishing to create an opening sufficient for unlawful removal of larger goods).

In this description, reference will primarily be made to a panel or panels for closing a cargo container of a goods carrying vehicle, though it will be understood that the

sliding latch could equally be used for all sliding and hinged panels.

Often a delivery driver will leave his vehicle rear door or doors unlocked whilst carrying goods into a customer premises, because of the difficulty and inconvenience of securing the door(s) whilst carrying or manoeuvring the goods. Valuable merchandise can thus be stolen from the vehicle, for instance whilst the driver is in the customer premises.

DISCLOSURE OF THE PRIOR ART

Smaller delivery vehicles are typically fitted with an inbuilt "rotary" type lock securing two hinged rear doors, but a determined thief can often quickly "burst" such a lock by a sudden blow from inedge the vehicle.

It is also known for a padlock to be fitted between two adjacent (hinged or sliding) vehicle doors, for instance for a vehicle parked overnight or otherwise unattended, but the fitting can often be forcibly removed, as by a sudden blow delivered from outside the vehicle.

Latches are widely used as fastenings for gates and doors, and consist of a bar or bolt that may be slid or moved into an aperture; the aperture will typically be formed in the gate or door frame, or in a member affixed thereto. A bolt

is known to provide substantial "burst strength", being strong against bending and shear forces.

In another closure arrangement single panels, for instance ones hinged to an outer frame, are often held in the closed condition by a securement rod movable generally parallel to the hinge axis into or behind a keeper mounted on the frame; such an arrangement is known for railway wagon doors.

A further closure arrangement requires the securement rod to have two end formations engageable respectively with one of a pair of keepers mounted on or in the panel outer frame, with a keeper adjacent each end of the securement rod. A delivery vehicle may have one or two openable panels, for instance two rear doors each individually provided with such a securement rod, which in this arrangement is rotated about its longitudinal axis to effect keeper engagement and disengagement.

Usually the securement rod will have a lock bar extending perpendicularly to the rod longitudinal axis. If so, in both the above arrangements it is known for the rod to be pivotable about its longitudinal axis so that the bar can be swung alongside a retainer (or between two retainers); a known retainer is in the form of aligned plates upstanding from the door. In another known arrangement there is a staple upstanding from the door, the lock bar being slotted to form a hasp.

An advantage of these known retainer arrangements is that the bar and the respective retainer can both be mounted on the panel or door to be locked. One disadvantage is that typically a padlock is used to secure the bar to the retainer, but either the padlock needs to be large and so is inconvenient for regular use, or the retainer needs to be thin offering low security. Another disadvantage is that a padlock shackle can often quickly be cut by portable croppers. Yet another disadvantage is that spot checks indicate that the padlocks once removed e.g. for the first delivery away from the vehicle depot, may not be re-fitted by the driver. Quality padlocks if mislaid are expensive for the vehicle owner to replace. Two handed removal and replacement of a padlock may be needed.

A sliding latch, slidable between a securing condition and a non-securing condition, is needed which is both effective in operation and simple to make and fit. Such a latch is desirable for both sliding and pivoting panels, particularly the sliding or pivoted rear door(s) of a delivery vehicle.

Yet another closure arrangement is available, and is suitable for truck and van rear doors which are are vertically acting, typically being of "roller shuttering" comprising laths interconnected to rise and fall together as the door is respectively opened and closed. Unless the door is secured in its closed position, unauthorised persons can lift the door to remove some or all of the vehicle contents. Furthermore, unless the locking components are housed so as

to be at least in part hidden from view, unauthorised persons can access the locking mechanism to break or by-pass it.

For a typical "roller shutter" installation, provided as a closure for a cargo container of a goods carrying vehicle, to each side of the opening is disposed a channel-like guideway. Several hingedly-interconnected, elongate and substantially flat laths or panels are slidably carried by the guideways, retained at their shorter edges by the guideways and with the panels spanning the opening.

Known roller shutters for the cargo containers of goods vehicles are designed to be secured in the door closed position by a closure device connected to one panel of the shutter (usually the lowest in the door closed condition) , the device being adapted to engage a keeper mounted in the container floor.

The closure device comprises an operating handle movable between an "open" condition and a "closed" condition, and with a hook connected to the handle, the hook being engageable with the keeper when the shutter and handle are both in the closed condition; a bracket carried by the door is positioned so that a padlock or the like may be used to secure the handle to the bracket, whereby to locate the handle in the closed condition and thus in turn to secure the shutter against unauthorised opening. Such a closure device is shown, for example, in UK Patent 1,233,385 and in UK patent 1,317,146.

Some of the disadvantages of this known device are shared with the previously described devices, i.e. that a padlock of suitable strength _. is_ relatively expensive, that the padlock may be mislaid, that the padlock may not be used to re-secure the door during a delivery e.g. if the deliveryman has to walk to and from the vehicle several times in order to unload the goods at a delivery point, that the padlock has an exposed shackle which can be accessed to be severed by a suitable tool; and that the device has a large number of parts.

DISCLOSURE OF THE INVENTION

We seek to utilise a bar or bolt, assembled with strong support members able to sustain substantial bending and shear forces, preferably comparable to those sustainable by the bolt. We further seek a preferred design adapted for the simultaneous use of more than one bolt.

According to one feature of the invention, we propose a sliding latch which includes a bolt, bolt guide means for axial sliding of the bolt between a latch engaged condition and a latch disengaged condition, and retaining means to hold the bolt in the engaged condition, the latch having a movable bolt retaining means and a lock operable to prevent movement of the retaining means.

Thus, we propose a sliding latch comprising a bolt, and with lock controlled retaining means for the bolt, the latch having an engaged condition in which the bolt is retained by the release means, and a disengaged condition in which the bolt is not retained by the release means.

In a preferred arrangement, resilient bias means urge the bolt towards the latch disengaged condition; thus, when the release means is unlocked, the bolt is urged resiliently towards the latch disengaged or open condition. The retaining means will preferably move perpendicularly to the bolt longitudinal axis e.g. perpendicularly to the bolt operating direction towards and away from the latch engaged condition.

According to another feature of the invention, we propose a sliding latch comprising first and second housings, a bolt slidably mounted in the first housing, and a lock controlled retaining means for the bolt in a second housing.

We also propose a panel with a first housing, the said first housing carrying a bolt, the bolt being slidable relative to the housing, and means to mount the panel for movement of the first housing relative to a second housing, the second housing carrying a lock controlled release means for the bolt. In use the release means will be concealed from view, and protected from tampering.

According to a further feature of the invention, we propose a sliding latch comprising first and second housings having a gap therebetween, a bolt mounted in one of the housings and receivable in the other of the housings, means for mounting the housings to a panel with the bolt spaced from the panel whereby a lock bar can be trapped between the bolt and the panel, and lock controlled release means for the bolt.

Usefully the bolt can be a plate which conceals the lock bar in the locked bolt condition; suitably the lock can engage directly with the bolt for locking, or indirectly by way of a latch plate. The housings can be parts of a one-piece assembly, or be separate housing members.

We also propose a sliding latch assembly comprising first and second housings, a bolt slidably mounted in the first housing, the bolt being slidably receivable in the second housing, a lock-controlled retaining means for the bolt in the second housing, and support means for the first and second housings adapted to hold the housings against relative movement, the housings having a bolt traverse gap therebetween.

Both of the first and second housings can have an extension, whereby the housing extensions can abut as an aid to initial alignment and mounting to the support means, without however the extension(s) intruding into the gap.

Preferably the support means is a hinged panel, such as a delivery vehicle door, but alternatively is a slidable panel. The bolt traverse gap will be of a size to receive a lock bar of a pivotable securement rod, whereby the bolt can pass over or perhaps through the lock bar to hold it (and thus the securement rod) against pivotal release movement.

The lock will be operated by a key or equivalent, of light weight and small size, readily retained by the driver e.g. on the vehicle key ring, and quick and convenient to use.

According to yet another feature of the invention, we propose a sliding latch assembly comprising first and second housings, a bolt slidably mounted in the first housing, and a lock controlled release means for the bolt in a second housing, characterised by first and second catch members, one of the catch members being mounted to the bolt and the other of the catch members being mounted to the second housing, the catch members having a first condition in which the bolt is withdrawable from the second housing and a second condition in which the bolt cannot be withdrawn from the second housing.

Preferably the bolt has a hollow section in which the first catch member is a pivotally mounted plate, with the second catch member being a pin extending between opposite side walls of the second housing and engageable (in the second condition of the members) by a coupling portion of the first catch member, as when the bolt is fully inserted into the

second housing. In an alternative embodiment the pivoted catch is mounted in the second housing and the pin in the bolt.

Desirably the catch members are positioned such that the bolt has two inserted positions in the second housing, namely a first inserted position in which the catch members are not aligned and a second position in which the catch members are aligned (and urged into the second condition). Thus sliding movement of the bolt from the first condition and into the second housing whilst still having a portion retained in the first housing initially achieves the first position wherein relative lateral movement of the housings is prevented by the bolt, and thereafter achieves the second position and condition in which relative lateral movement of the housings is still prevented but in addition the bolt cannot be withdrawn until the catch members are disengaged, as by a key operated release means. The first position can be used on a fitted vehicle or similar assembly "carrier" to permit temporary securement (as whilst loading a vehicle in a secure environment such as the manufacturer's depot), and the second position in other environments (as between trips transferring part of the load at customer premises).

In the second condition of the catch members, engagement of the catch plate with the pin or other retainer acts to prevent withdrawal of the bolt until the catch plate is disengaged from the retainer. Usefully, the disengagement of the catch plate is effected by a cam-type lock which is

rotated to lift the catch plate or equivalent pivoted lever to effect its release from the retainer whereby to permit the bolt to be withdrawn into the first housing.

Desirably the bolt is in the form of a block having a central cut-away recess in which the catch plate can be received, and in which it can pivot. In an alternative embodiment, the catch plate can be mounted to one side of the bolt, for instance in a side slot in a bolt of generally rectangular cross-section.

Although the housings can be cut from solid, usually of metal, alternatively thay can comprise interconnected side plates. Thus the side plates of the first housing can be joined by edge plates (which typically will be horizontal in their position of use). The second housing can in addition have the side plates interconnected by the catch retainer if this is in the form of a bar extending between the side plates.

Although such retainer bar can be welded in position, it may be a force fit between aligned apertures in the side plates of the second housing; when assembled to a panel such as a vehicle door, a force-fit bar is prevented from being "punched out" (for unlawful release of the catch) since the housing when connected to the panel has the panel material as a backing.

We also propose a panel fitted with one of the housings according to the invention.

We also propose an arrangement which includes a first panel, the first panel having mounted thereto one of the housings according to the invention and which is alignable with the other of the housings according to the invention, the said other of the housings being fitted to one of another panel and a frame member for the first panel.

As another further feature of the invention we propose a sliding latch which is useful in particular for attachment as original equipment or as a retro-fit to a roller shutter door. Specifically we seek to reduce or avoid the requirement for the bracket and padlock of the known closure device.

Thus in one embodiment we propose a sliding latch for a roller shutter, the roller shutter having a closure device including an operating handle, the handle having an open condition and a closed condition, the latch comprising a bolt, and with lock controlled retaining means for the bolt, the latch having an engaged condition in which the bolt is held by the retaining means, and an openable condition in which the bolt is free of the retaining means, and in which the bolt has a portion locatable adjacent the handle when the latch is in the engaged condition and the handle is in its closed condition, the said portion preventing movement of the

operating handle from its closed condition to its open condition.

The said portion of the bolt may be a ledge, preventing movement of the handle in one direction only, though preferably it will be an "L" section, preventing movement in two directions. Alternatively, the portion may be a "U" section, or a box section, encompassing part of the handle.

In many designs of closure device, the operating handle, when in the closed condition, projects substantially parallel to the longer edges of the shutter panel mounting the sliding latch of our invention; the sliding latch will be mounted on the panel so that the bolt will slide within the latch housing in a direction substantially parallel to the (closed) handle i.e. between the openable and engaged conditions.

However, if the operating handle, when in the closed condition, projects at an angle to the (upper) longer edge of the lowest shutter panel, the sliding latch can be mounted on a neighbouring panel. Alternatively the sliding latch can be of modified form, permitting it to be mounted on the lowest panel, but with its bolt slidable at an angle to the (closed) handle longitudinal axis.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described, by way of example, with reference to the accompanying drawings, in which:-

Fig.l is a side sectional view of one embodiment of the invention, in the latch engaged condition, locking two doors;

Fig.2 is a plan sectional view of another embodiment of the invention, in the latch open condition, with gap covering means carried by the first housing;

Fig.3 is a front view of one embodiment of a retaining means for a pair of bolts;

Fig.4 is a front view of another embodiment of a retaining means for a pair of bolts;

Fig.5 is a partial side view of an alternative embodiment of bolt;

Fig.6 is a view of the bolt of Fig.5, riding over a retaining means during latching;

Fig.7 is a perspective view of a first housing being fitted to a securement block;

Fig.8 is an exploded side sectional view of another embodiment of housing being fitted to a panel with a securement block;

Fig.9 is a perspective view of yet another embodiment of housing being fitted to a panel with a securement block;

Fig.10 is an exploded perspective view of first and second housings in the latch engaged condition;

Fig.11 is a front elevation of a door securement arrangement, with another embodiment of first and second housings according to the invention;

Fig.12 is a side view of a door securing arrangement according to Fig. 11, fitted with a concealment plate;

Fig.13 is a front view the arrangement of Fig.12;

Fig.14 is a perspective view of an alternative embodiment of latch;

Fig.15 is a perspective view of another alternative embodiment of latch according to the invention, in the bolt disengaged condition;

Fig.16 is a partially cut-away perspective view of the bolt of Fig.15;

Fig.17 is a perspective view of a bolt and second housing of yet another alternative embodiment;

Fig.18 is a part-sectional view of a first and second housing of a further alternative embodiment;

Fig.19 is a perspective view of the embodiment of Fig.18, fitted to the rear doors of a vehicle;

Fig.20 is a partial view of the roller shutter of a cargo container, with a known closure device fitted to the lowest panel, and a sliding latch according to the invention securing the handle of the closure device in the closed condition;

Fig.21 is a perspective view of the sliding latch of Fig.20 in the engaged condition, before attachment to a panel;

Fig.22 is a plan view of the sliding latch of Fig.21, with the cover removed;

Fig.23 is a plan view of the cover of the latch of Fig.21;

Fig.24 is a partial view corresponding to Fig.20 of the lowest roller shutter of a cargo container but

fitted with a second known closure device, and a sliding latch according to the invention securing its handle in the closed condition;

Fig.25 is a top plan view of an a panel, its end located in a channel guideway; and

Fig.26 is a view corresponding to that of Fig.25, but of another panel, suitable for securement against vertical movement.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In the following description, similar parts of the various embodiments carry the same numbers.

Vehicle rear doors 10,20 are hung upon side-hinges (not shown), and so can pivot from the "straight-line" position of Fig.l to the "part-open" position of Fig.2 unless restrained by the sliding latch of the invention. Respective parts of the latch as more fully described below are mounted in first housing 11 and second housing 21. In an alternative embodiment the doors 10,20 are slidably mounted, and as viewed in Fig.l are movable leftwards and rightwards.

The first housing 11 comprises a side plate or base 12 and integral (upstanding in this view) edge members 13 joined by another side plate or cover (not shown) to form a box

assembly, rectangular in cross-section, and with at the inner end (in use) a closure plate 14. A support member or strengthening plate 15 is secured to base 12 and to edge members 13. In an alternative embodiment, the first housing is formed from a flat sheet, bent to a rectangular cross- section about plates 14,15, and with the butting plate ends welded together.

Plates 14,15 have aligned apertures 16, shaped and sized slidably to receive a bolt 17. In this embodiment, for extra security there are two bolts 17 and with therefore each plate 14,15 having a pair of apertures.

Bolts 17 are mounted upon outer plate 18, which in this embodiment carries a finger-grip 19, which can be used to effect withdrawal of the bolts 17 to the left as viewed.

Outer plate 18 slidably fits within the first housing 11, and this arrangement may be preferred if water or rain ingress into the housing is to be inhibited, notwithstanding any slight differences which might occur in the locked position of outer plate 18 relative to the housing due to manufacturing tolerances; however, the outer plate 18 can have the same cross-section as the first housing, and so butt thereagainst in the normal locked condition of bolts 17. In an alternative embodiment, the bolts are secured to a plate slidably retained within the housing 11, and an elongated grip extends from the plate through an aperture in a fixed end wall of the housing.

Between strengthening plate 15 and outer plate 18 there is a resilient means (not shown), typically a coil spring but alternatively a group of Belleville washers, urging the bolts 17 to the left as viewed i.e. towards the latch open condition. In another embodiment a resilient means is additionally or alternatively located against inner closure plate 14 and acting against cupped retainers mounted on one or more of the bolts 17.

The second housing 21 in the embodiment of Fig.l has the same cross-section as first housing 11. There is an inner end plate 24 and a strengthening plate 25 each of which has apertures 26, aligned one to the other and in the position of use (as shown in Fig.l) aligned also with apertures 16. The inner ends of bolts 17 can thus pass through apertures 26.

Between strengthening plate 25 and outer end wall 29 is a lock chamber 30. Within lock chamber 30 there is a retaining means in the form of a lock plate 31; lock plate 31 is slidably guided (towards and away from the top of the page as viewed in Fig.l) in slide channels formed by strengthening plate 25 and guide portions 39. Lock plate 31 has an upstanding ledge 32; movement of the lock plate 31 is controlled by bifurcated arras 33 of lock 34 which extend to either side of ledge 32.

Anti-clockwise rotation of the arms 33 can effect movement of ledge 32 to press the lock plate (downwards) into engagement with respective slots 35 (Fig.2) of the bolts 17, such

engagement inhibiting (leftwards) withdrawal of the bolts from second housing 21.

Clockwise rotation of arms 33 will lift ledge 32, to effect release of the lock plate from slot(s) 35, to permit withdrawal of the bolt(s) 17.

An advantage of an arrangement utilising bifurcated arms 33 is that an alternative latch design can be made permitting manual lock plate release, if lock 34 is not in the locked condition. Such manual release could be obtained in the Fig.l embodiment for instance by the provision of a (downwards) reduced-width extension of lock plate 31, the extension protruding through an opening in the lower edge member of the second housing. Manual release of the lock plate would be achieved by upwards pressure on the extension. In an alternative arrangement the lock plate has an upwards extension, protruding through an opening in the upper edge member for the second housing (or a sidewards extension protruding through an opening in the cover) , and which could be used to lift the lock plate, again to permit the bolts 17 to be withdrawn.

Embodiments with lock control but with the facility for manual release when the lock is disengaged could be welcomed by drivers. Such embodiments could have a first mode of operation wherein the lock is inactive so that the latch could be released manually, and have a second mode of operation wherein the lock is active, and release of the lock

is required each time the latch is desired to be opened. In secure environments, for instance when loading the vehicle at a depot, the latch could be operated in its first mode, so that there is no need for repeated use of a key to operate lock 34 (to lift the ledge 32 by clockwise movement of the lower of the bifurcated arms). However, when in non-secure environments, for instance when away from the depot, the latch could be operated in its second mode, with for instance upward lifting of the lock plate 31 when lock 34 is engaged being prevented by the upper of the bifurcated arms.

Thus as viewed the upper of the arms 33 can be alternatively used to prevent ledge 32 being lifted, and to return the ledge 32 downwardly to the latching condition; the lower of the arms can be used to lift the ledge 32, and perhaps also to inhibit damage to a lock plate provided with a manual release extension as above described, perhaps resulting from repeated violent impacts against the bolt, as by the unauthorised use of pliers to grip and reciprocate the extension.

In a preferred embodiment, means are provided to prevent withdrawal of the bolts 17 from the first housing 11. In such an embodiment there is a protuberance on each bolt and for which there is a corresponding recess 36a permitting the protubrance to slide therethrough i.e. as part of each aperture in the second housing, but not of aperture(s) in the first housing. Such a recessed aperture 36 is shown in Fig.3.

The protuberance will usually be provided after fitting the bolt(s) into the first housing, perhaps by a circlip fed over the exposed end of the bolts and retained in a shallow groove.

In the embodiment of Fig.2, for additional security the first housing 11 carries an L-shaped overlay 40, welded or otherwise secured to the edge member 13 and to the cover, and which in the closed condition of the doors 10,20 will obscure the gap between the housings 11,21, preventing unauthorised access thereto. The edge member(s) 13 and/or the cover of the first housing 11 can be extended so as to provide an indicator of the design spacing between the fitted housings in their locking condition, to assist installers. In an alternative embodiment the overlay can be U-shaped in section, extending over part or all of both of the edge members as well as the cover.

In the embodiment of Fig.3 the lock plate 31 is urged upwardly (as drawn) towards its released condition by springs 43 acting between lower edge member 22 of the second housing and limbs 46 of the lock plate. For this embodiment only the upper of the arms 33 of the lock 34 (Fig.l) needs to be provided, with the locking plate being resiliently urged to disengage from the slots 35 upon clockwise movement of upper arm 33, typically by key operation of lock 34. In an alternative but less secure arrangement, lock 34 can be

rotated by hand between a lifted and non-lifted condition of lock plate 31.

As viewed in the alternative arrangement of Fig.4, the lock plate 31 moves to the right in order to disengage from the sliding bolts; this arrangement has the advantage that the key entrance for the rotary lock is through an edge member of the second housing rather than through the cover plate and can thus be concealed from normal view in its position of use.

In an alternative embodiment the lock plate can be in the path of bolt(s) 17 during their insertion movement into second housing i.e. towards the locking condition. As seen in Figs. 5 and 6 the or each bolt has an angled lead-in portion 50 and is pivoted at 51. Thus the lead-in portion 50 rides up and over the (upper) surface 52 of a lock plate, before dropping under its own weight into the locking condition i.e. with lock edge 53 held against leftwards withdrawal (as viewed) by the lock plate. In a further alternative embodiment the pivot 51 includes a torsion spring urging the lead-in surface towards the position of Fig.5, away from the position of Fig.6.

In the embodiments of Fig.5,6, as viewed the lock will move the lock plate 31 downwardly when withdrawal of the bolt(s) is required.

For some installations, when it is not convenient to weld the housings 11,21 directly to the respective vehicle doors, securement blocks may be required. Fig.7 shows a block 70, used to secure the first housing 11 to a door or panel (not shown). The block 70 is secured to the door by screws passing into tapped apertures 72 or bolts passing through countersunk apertures (used in place of tapped apertures 72) for retention by nuts located within the countersunk portion. The housing 11 is mounted, as by welding, to a flange 74, adapted to fit beneath an undercut lip 76 in the block. In this embodiment the flange 74 also has apertures 80 through which screws may pass, into threaded holes 82 in the block 70, to secure the housing 11 to the block 70. The second housing 21 may be secured to a similar block in similar fashion.

Fig.8 shows another securement block 90, for securing a second housing 21 to a door 20. In this embodiment, block 90 is a primary block, and there is also secondary block 92, which has two (or in an alternative embodiment more than two) upstanding bolts 94 which will pass through corresponding holes 96 made in the door 20, and through holes 98 in the secondary block 90, whereby the primary and secondary blocks can be secured together by nuts (not shown) so sandwiching the door. Desirably the nuts will be received in recessed portions 100 of the primary block 90 so that they do not stand proud.

The housing 21 is secured to a slide plate 74 as in the Fig.7 embodiment, and will be secured to the primary block 90 by screws passing through apertures 80 in flange 78, and into holes 82, as described in relation to Fig.7.

Preferably, the housings are slid into position and coupled to the respective blocks 70,90 when the vehicle doors are open, such that the screws will be concealed when the doors are closed. In an alternative but less preferred embodiment a housing can be secured to the respective block simply by screws passing through an upstanding lip, undercut or not, and preferably through a portion of the lip concealed when the vehicle doors are closed, as by the facing lip of the secondary block for the other housing.

Fig.9 shows a perspective view of yet another embodiment of second housing 21 being fitted to a panel 20 with a primary block 90 and secondary block 92. In this embodiment, the secondary block 92 has four upstanding bolts 94 which pass through respective apertures 96 in the panel 20, and into holes 98 in the primary block 90.

Fig.10 shows an exploded perspective view of a first housing 11 and a second housing 21, both of which are secured by primary blocks 70,90 to their respective panels (not shown). Both primary blocks 70,90 are engaged by the upstanding bolts 94 of respective secondary blocks 92. The housings are shown in the latch engaged condition i.e. in which the panels will be secured in the closed condition. It will be understood

that an overlay, as described in relation to Fig.2, may be fitted to one of the housings, to obscure the gap 110 between the housings.

In the arrangement of Fig.11, the panel or door 10 is hinged at 100 for outward swinging from the closed position shown to the door open condition i.e. out of the paper as viewed. In an alternative embodiment there are two doors, both correspondingly hinged in known fashion, and both fitted as described below with a lockable securement rod.

Thus as seen in Fig.11, vehicle unloading door 10 is fitted with a securement rod 101 having an integral lock bar 102 extending perpendicularly therefrom. The upper and lower ends of securement rod 101 are received in respective keepers 103 mounted to fixed outer door frame 104, to hold the door 10 against hinged opening movement. In this condition the bar 102 can fit into a gap 105 between housings 11,21, and for this purpose both of these housings in this arrangement are mounted in fixed alignment upon the door 10, which door 10 thus acts as support means for the housings.

With the bar 102 in gap 105, each bolt 17 can pass over the bar, which is thereby trapped between bolt 17 and the adjacent part of door 10; in an alternative but less preferred embodiment the or each bolt 17 can pass through a respective aperture in the bar. Thus the bar can be held in this position by the bolt(s), and held against unauthorised movement when the bolt(s) are locked in position.

Pivoting of the securement rod about its longitudinal axis, after unlocking of the bolt(s), releases bar 102 from between the housings, permitting the securement rod to be rotated out of engagement with keepers 103 and the door 10 to be opened. In an alternative embodiment the securement rod can be lowered or lifted out of engagement with a single keeper fixed adjacent its upper and lower end respectively.

in a preferred embodiment the housings are formed as a one- piece assembly (Fig.14) joined by intermediate section 106. Alternatively one or both of the housings 11,21 has a corresponding extension, which is adapted for location against the panel or door 10 to aid in initial fitting of the housings, both to control the separation between the housings and thus the designed gap 105 into which the bar 102 will fit, and as an abutment to inhibit weakening of the door panel from repeated impacts by bar 102.

in a preferred embodiment of Figs.12 and 13, the bar 102 is fitted with a concealment plate 107, which when in the door locked condition covers gap 105. As also shown in this embodiment, there are three bolts 17 securing the bar 102. The concealment plate 107 helps inhibit access to that length of the bolts 117 exposed between housings 11,21. If the concealment plate is shaped for use as a handle to aid in pivoting movement of the bar 102 and lock rod 101, then bar 102 can be shorter, for instance with its remote end also concealed by plate 107.

In the Fig.14 embodiment, the bolt is in the form of a plate, which also acts as a concealment plate 207. Combination bolt and concealment plate 207 is slidably mounted in the housing, and in its position of protective use it is supported in both housing units 211,221 and so is not in cantilever. Plate 207 is not connected to bar 202, and slides perpendicularly thereto. For unauthorised opening of the associated panel it is first necessary to displace plate 207, and then separately to displace bar 202, with consequent extra protection.

In this embodiment the concealment plate 207 can be retained in housing part 221 by spaced arms (not shown) of lock 234 and which engage in openings 208. In an alternative embodiment the housing part 221 has aligned recesses in the inner surface of the upper (as viewed) wall of housing section 221, additionally to inhibit any attempted unauthorised leftwards movement of concealment plate 207 towards the non-concealed condition.

The combination bolt and concealment plate 207 can in an alternative embodiment be retained by a separate latch as described herein in relation to Figs.1-4 or Figs.15-18. Furthermore the latch can be in either housing part i.e. part 211 or 221.

Similarly the combination bolt and concealment plate can be resiliently urged to the left as viewed in Fig.14, i.e.

towards the unsecured condition with the concealment plate 207 removed from above the bar 202, towards (preferably into) housing part 210. Thus there can be resilient bias means in the form of a coil spring acting against the right-hand face of lateral projection 206, or against the stem of finger rod 219.

It will be understood that the combination bolt and concealment plate 207 effects the same holding function as the one or more (circular or rectangular section) bolts 17 of the embodiment of Figs.11,12.

The housing sections of an integral or one-piece housing and the separate housings of an alternative embodiment can be robust, since their size is not limited by the fitting requirements of an external padlock or the like, giving added inherent strength as compared with the conventional upstanding plates and permitting both greater freedom in bolt or screw positions as well as more secure fixing to the vehicle door or similar panel.

For the embodiment of Fig.15, in use, first housing 311, and second housing 321, are secured to adjacent sides of two pivoted doors (not shown), usefully the pivoted rear doors of a delivery vehicle. In an alternative embodiment, housing 311 is secured to a sliding (or swinging) door, whilst housing 321 is secured to a frame within which the door slides (or swings), whereby the door can when required be held against opening movement as more fully described below.

The first housing 311 carries bolt 317 which in this embodiment is in the form of a metal block of rectangular cross-section. The leading edge of the bolt 317 (to the right as viewed) is recessed to receive the catch plate or lever 348 (Fig.16); in an alternative embodiment the bolt 317 is in the form of a hollow housing assembled from side plates and an end plate.

Catch plate 348 has an angled lead-in portion 350, and is pivoted upon cross-pin 351. Catch plate 348 is biassed towards the position of Figs.15,16 by spring 360 (Fig.16), with its lower surface resting against the bottom of the recess in bolt 317 to prevent further (clockwise as viewed) rotation. In alternative embodiments the said further rotation of catch plate 348 can be prevented by an abutment connected between opposed sides of the bolt at a position spaced from the base of the bolt, with the advantage of helping to brace the bolt sides against deformation.

In an alternative but less preferred embodiment spring 360 can be omitted, with the offset weight of the catch plate being selected to ensure that the catch plate can drop to its second condition as shown.

The bolt 317 is spring biassed towards its first condition (leftwards or open as viewed) by a compression spring 343 acting between a boss 372 on the bolt and a boss 374 on the

inside of the first housing; in alternative embodiments the spring ends can act against recessed abutment(s).

In one embodiment the spring force becomes active as soon as movement of the bolt in the insertion direction commences, with the automatic ejection of the bolt from the second housing being prevented only when the catch members are in their second condition i.e. aligned and engaged.

In an alternative embodiment the spring position, size and characteristic is selected such that the spring force becomes active only after the bolt has been inserted part way into the second housing, whereby the bolt can adopt an "intermediate" condition in which it straddles the gap between the housings and is inserted only part-way into the second housing i.e. sufficient to prevent relative transverse movement of the housings but insufficient for the catch member and retaining member to be aligned and engaged. Thus for a (fitted) arrangement, the authorised panel operator e.g. vehicle driver or the like, may have the facility to move the bolt into the second housing to the intermediate condition i.e. not so far as to effect locking engagement as with lock-pin 331, but even in this intermediate condition the doors will not open because of the "strut" provided between the housings by the bolt. In such an embodiment, the spring 343 becomes operative to urge the bolt to the leftwards condition only after the bolt has partially entered the second housing; thus there is some free movement between the bolt and the first housing. An advantage of this

embodiment is that the intermediate and non-locked condition of the doors can be used in secure situations (as in the depot) even though the doors still need to be kept closed between loading operations e.g. against rain ingress, but when repeated unlocking by the use of a key may be inappropriate or unnecessary.

In use, lead-in portion 350 rides up and over the upper edge of lock-pin 331, before spring 360 urges the catch plate into the locking second condition, with the lock edge 352 held against leftwards withdrawal (as viewed) by the lock pin 331.

To release the bolt 317 the catch plate 348 is lifted, in this embodiment upon rotation of lock 334, which conveniently is a known cam-type lock with the cam usefully engageable with part of lead-in portion 350.

It will thus be understood that if the first and second housings are secured to respective opening doors (or to a door and an associated frame part), sufficient movement of the bolt 317 to the right (as viewed) automatically effects inter-locking of the housings and thus of the door(s), with unlocking only possible by the use of a key in lock 334.

In the alternative embodiment of Fig.17, the retaining lock pin 431 is located between side walls of the hollow or recessed bolt 417, whilst catch plate 448 is located in the second housing 421. The bolt 417 is slidably mounted in a

first housing (not shown) but which could be the same housing as used in the embodiment of Fig.15 i.e. housing 311.

The second housing 321,421 will have its rear end closed, both to prevent unauthorised access to catch plate 348,448 by those seeking to pivot the catch plate without use of a key, and to limit the movement from left to right (as viewed) of the lock bolt 317,417. In this embodiment the catch plate has a surface 453 angled rearwardly i.e. that surface which faces lock edge 352, and to prevent the catch plate inadvertently being disengaged (as by this surface "riding up" retaining pin 431); the positions of the pin and of the rear end of the second housing are selected so that part of the catch plate will abut the rear surface before the catch plate has been so lifted.

When so abutting the rear closure of the second housing (if the position of pin 331 permits this in relation to the gap behind lock edge 352) there can be some play between pin 331 and the lock edge 352 in the embodiment of Figs.15,16, or pin 431 and the surface 453 in the embodiment of Fig.17, the amount of play being determined by the designer.

The embodiments of Figs.15,16 and 17 may have a securing overlay obscuring the gap between the housings. Such an overlay is described herein in relation to Fig.2.

In the embodiment of Fig.18, the retaining lock member is an upstand part 531 integral with bolt 517. Thus in a preferred

embodiment the bolt 517 can be made solid (rather than hollow or recessed), as can the lock member.

One side face of bolt 517 (the rear face in use) carries a protruding abutment pin 582 which rides in a slot 584 in a side wall of the first housing 511. In use, the slot 584 is hidden from view, being in the (rear) wall 513 of housing 511 i.e. that wall of housing 511 which in the fitted condition is adjacent to the supporting panel (not shown but typically a vehicle door 510 of Fig.19 and to which housing 511 is secured) .

The bolt 517 is urged to the unlocked condition (from right to left as viewed) by spring 570, which acts between a fixed part 511a of housing 511 and the bolt surface 517a; in this embodiment fixed part 511a upstands from the side wall 513 of the housing 511.

The catch plate 548 is resiliently biassed towards the engaged condition by a spring 560.

In use, in this embodiment wherein the housings are each fitted respectively to a pivoted closable door for a delivery vehicle, after the first (511) and second (521) housings have been brought together upon closure of both doors, bolt 517 is pushed to the right as viewed; the upstand 531 engages a lower cam-shaped part 549 of catch 548 whereby to lift the catch against the force of spring 560, until with further rightwards movement the catch pivots clockwise into coupling

engagement with bolt 517 i.e. behind upstand 531. When so coupled the bolt thereafter cannot be released (to the left as viewed) until catch 548 is rotated clockwise, as by a key (not shown in this drawing).

In the embodiment illustrated, the housings 511,521 can respectively be secured to the rear doors 510,520 of a vehicle, or one can be secured to a door, and the other to a frame. Many (heavier) freight vehicles however have securement rods 101, as shown schematically in Fig.19, which typically engage top and bottom door frame members. For such vehicles, and as shown in the embodiment of Fig.19, the housings 511,521 are secured, as by welding, to support blocks 571,572 respectively. The support blocks 571,572 each have an aperture 574 sized to bridge the securement rods 101, whereby the blocks can be secured as a retro-fit i.e, after the securement rods are in place. Thus the doors can be secured both by the securement rods in conventional manner and by the housings and bolt of this invention.

In an alternative embodiment, each of the housings 511,521 is deepened to provide the open-sided aperture in which the securement rod can fit. In yet a further embodiment, suitable for fitting to vehicle during vehicle assembly, the aperture is not open sided i.e. the securement rods 101 pass through the housing extensions. An advantage of the bolt and housings of these embodiments therefore, even if the securement rods 101 are cut through or otherwise severed during attempted unauthorised opening of the vehicle doors

510,520, those doors are still held against opening by the housings 511,521 and their associated bolt 517.

The gap which would otherwise be visible between housings 511,521 when the bolt has been secured, and which might be used for unauthorised insertion of an opening tool, is in this embodiment covered by a U-shaped straddling member 540, carried by (welded to) the second housing 521 since in this embodiment this housing is connected to the door 520 which is the last to be shut and the first to be opened in use. However, in an alternative embodiment, the straddling member may be secured to the first housing, if door 510 is the last to be shut and the first to be opened.

Fig.20 shows the sliding latch used on a roller shutter door. The roller shutter 601 of Fig.20 comprises a plurality of elongate panels or laths 602, retained as seen in the embodiment of Fig.25 at their shorter edges in guideways 603 carried by jambs 600, the jambs defining the sides of a door opening which the roller shutter can close.

Each intermediate panel 602 is interconnected to the respective adjacent upper and lower panels by hinges (not shown) along the longer edges 604. The guideways 603 of a typical cargo container are substantially straight to either side of the container rear opening and extend upwardly, but towards the uppermost region of the opening curve forwardly and then continue parallel to the underside of the roof of the cargo container, the guideways 603 and the hinged panel

interconnections being arranged to permit the door to be stowed (when open) largely or wholly within the container.

The interconnected panels 602 are retained between the guideways 603, so conversely when the door is closed (with the shutter pulled down), the panels co-operate to provide a substantially flat surface closing off the opening.

In the embodiment of Fig.20 a known closure device 605 is fitted to the lowest panel 602a of the roller shutter 601. This is the known installation, and closure device 605 can be fitted to a newly-assembled door together with the sliding latch of the invention, or closure device 605 can be left in position if already fitted to a door in current use but with the associated locking components (not shown) removed and replaced by the sliding latch of the invention.

The known closure device 605 comprises a handle 606, a hook 607, and a keeper (not shown). The keeper comprises a cup- shaped housing with a cross-strut, and is fixed into the floor 608 of the container; in the secured condition shown the hook 607 fits below the cross-strut to secure the lower panel 602a and thus the door against being lifted. The handle is mounted upon pivot 610 carried by the panel 602a, and so when turned from the position shown sufficient to release the hook from under the cross-strut can be used to lift and lower the roller shutter forming the container (rear) door.

In the door locking condition, with the hook under the cross- strut, the sliding latch and handle co-operate such that the free end of the handle 606 is encompassed by the bolt of the sliding latch. Thus as more clearly shown in Fig.21, the sliding latch 609 comprises a hollow bolt 617 slidably mounted in a housing 611, the hollow bolt 617 being sized to receive the free end of the handle i.e. the end opposite the hook 607. Thus with the free end so received, handle movement in the opening direction is prevented or restricted.

In an alternative embodiment only that portion of the bolt 617 intended to receive the free end of handle is of box section, comprising outer walls 617a,b,c and d, with the remainder being solid.

Wall 617d is extended beyond side walls 617a,c to provide flanges 619 which slide within guide channels 620 of housing 611.

in a further alternative embodiment of sliding latch, the portion of the bolt locatable adjacent the handle is a ledge, such as may be provided by wall 617a; in yet a further alternative embodiment the portion is an "L" section, such as may be provided by walls 617a and 617b; and in a yet another alternative embodiment the portion is a "U" section, such as may be provided by walls 617a,b and c. The alternative "ledge" embodiment is less preferred, though suitable for some applications, since it might in certain installations be

possible for the handle to be forced away from the panel and around the ledge.

The housing 611 comprises a pair of edge walls 611a,b, a top cover 611c, and a slide portion 615. The slide portion 615 extends (to the right as viewed) beyond the edge walls 611a,b and the cover 611c.

The bolt 617 is slidable within the housing 611, its outwards travel (to embrace the handle) being however limited in this embodiment by the engagement of an end plate 625 with the edge walls 611a,b and cover 611c of the housing. The end plate 625 is secured to the right-hand (as viewed in Fig.21) ends of walls 617a,b,c. In use the bolt 617 may be slid with respect to the housing by finger or hand pressure on the end plate 625, the sliding surfaces being greased or otherwise lubricated for this purpose when the latch is in the Fig.21 condition.

As shown in Figs.22 and 23, a lock controlled retaining and release means is located beneath the cover 611c of the housing, i.e. in the region between the cover 611c and the wall 617b of the bolt.

Thus pivotally secured to the wall 617b of the bolt is the catch plate 648. A spring 660 biases the catch plate 648 anti-clockwise against limit stop 662 to the position shown. Spring 660 acts between the catch plate 648 and a filler plate 627, also secured to the wall 617b of the bolt. Filler

plate 617b is of a thickness equal to the difference in height (as viewed in Fig.21) between the edge walls 611a,b of the housing, and the top surface of the wall 617b of the bolt. The filler plate 627 will occupy the gap between the wall 617b of the bolt and the cover 611c of the housing, so that, even in the fully retracted condition of the latch (as shown in Fig.22), the region between the cover 611c and the wall 617b is closed off, and the lock controlled release means is protected from damage and dirt ingress.

In alternative embodiments, it may be acceptable for a part of the lock controlled release means to be visible when the latch is in the retracted condition.

Fig.23 shows the cover 611c of the housing. On the underside of the cover 611c is secured the upstand 631, engageable by the catch plate 648. In this embodiment, upstand 631 is integral with filler piece 629, of the same thickness as filler piece 627, and which also closes off the region between the cover 611c and the wall 617b.

Fitted to the cover 611c is the lock 34, which in this embodiment is a lock operating a cam which, when the latch is in the engaged condition, can force the catch plate against spring 660, releasing lock edge 652 from upstand 631, thus the latch is in its openable condition. In an alternative embodiment, a release spring can be included to bias the sliding latch away from its engaged condition, so that it is

necessary to push the bolt 617 against the action of the release spring to engage the catch plate with the upstand.

In the embodiment of Fig.24, the operating handle 706, when in the closed condition shown, projects almost perpendicular to the longer edges of the shutter panels. Thus, there is insufficient space on lower panel 602a to locate the latch of Figs.20-23. In this embodiment, the handle must be moved leftwards (as drawn) from the open position shown in dotted outline to the closed condition shown in solid outline.

The sliding latch includes a modified bolt 717, which has an L-shaped portion 720 locatable adjacent the handle in the closed condition. The bolt slides relative to the housing 709 until the portion 720 is adjacent the handle, preventing movement of the handle to the open condition.

An advantage of our arrangements is that the bracket of the known closure device is not required, and so for a new door is not fitted, or for a retro-fit e.g. if the sliding latch is fitted to an existing roller shutter, can be removed.

These embodiments provide a latch which for most applications travels to its engaged condition by movement substantially parallel to the longitudinal axis of the handle, with as much of the lock handle being covered in its engaged condition as the designer or installer decides, the bolt preferably being hollow to enclose or embrace the free end of the handle

whereby to inhibit movement in all directions other than towards the handle pivot 610.

In the embodiment of Fig. 25 all but one of the laths 602 are retained in guideways 603 carried by door jamb 600, by way of rollers 598 mounted on axles 599. The remaining lath, shown in Fig.26, does not have a guide roller, and so its axle can be encompassed by the hollow bolt 617 (Fig.21), slidable as above described in housing 611; to permit the bolt to encompass the axle (a) this axle is located substantially centrally disposed (fore and aft) of guideway 603 by its interconnection with the upper (and preferably lower) lath, and {b} the hollow bolt in this embodiment is internally tapered so as to provide a large initial diameter difference but to more tightly fit around the axle the more the latch is extended out of the housing i.e. the more the axle is enclosed.

In this embodiment guide 603 of Fig.26 is apertured such that the housing front face fits flush with the outer guideway surface, with therefore the latch able to project forwardly from the housing as shown in Fig.21, into the guideway and around the axle 599.

Usefully a second housing is mounted to the opposite door jamb, at an aligned position with the first housing, for balanced two-position locking. Other advantages of this arrangement are that the handle 606 can be used only for lifting and lowering the door i.e. without a keeper being

provided, or perhaps if the keeper is retained or provided the handle can cooperate with the keeper for temporary holding of the door in the secured condition e.g. whilst at a protected location such as the vehicle depot; and that the need to clean and drain the keeper housing may be avoided.

For extra security, more than one panel or lath 602 can have edge locking, and/or these edge locks can be used with the floor lock of Fig.20.

Although we foresee particular advantages for the described arrangements for securing the hinged or sliding door(s) of delivery vehicles, the arrangements could be used for other vehicles, or for other applications e.g for sliding or hinged (glazed) panels such as are used for patio windows.

Also, whilst we foresee that the embodiments described in relation to roller shutter doors will have their greatest advantage with vertically operating doors, our sliding latch can be used with horizontally operating doors (usually solid), and for applications other than for vehicle cargo doors. As one example of other uses, the embodiment of Figs.25,26 can be used for releasably securing the platform of a vehicle load lifting apparatus e.g a tail lift, in a vertical raised stowed condition (to prevent inadvertent descent of the platform during vehicle movement, with consequent damage to the vehicle and perhaps to other road users) .