Commercial vehicles may be the target of pilfering. One risk faced by vehicle owners and drivers is where the driver leaves the door unlocked while making deliveries. This may be because it is inconvenient for the driver to lock the vehicle. For example, locking may be a two-handed operation. if the driver has just taken an armful of goods from the vehicle, he will be tempted to take a chance rather than put the goods down, lock the vehicle and then pick the goods up again. In addition, even if the vehicle is locked, it may be too easy to force open the door. Sliding or roller shutter doors are a particular problem because it may be possible to jemmy them open relatively easily.

Thus one object of the invention is to provide a secure lock for a sliding or roller shutter door, for example the rear door of a commercial vehicle, which will lock the door automatically when closed.

Another object of the invention is to provide a lock which is of simple and rugged construction and which can be made more resistant to jemmying than some prior art locks.

Our Patent Application no. W098/40590 discloses a lock which enters the locked state when closed but it requires an actuator to hold back the lock bolt in the open position and this increases the complexity of the lock. Thus, a third object is to provide a lock which does not need any actuator to hold back the lock bolt in the open position. According to one aspect the invention, there is provided a locking arrangement for a vehicle door, the arrangement comprising a first locking member which in an unlocked condition is engageable with a second locking member and during closure of the door moves to a locked condition in which it is latched by latching means to retain the second locking member and thereby prevent opening of the door, the latching means being coupled to a lock and the first locking member being biased to its unlocked condition whereby unlocking the lock unlatches the first locking member to release it and allow the door to be opened.

By coupling the lock preferably a pin tumbler lock barrel to the latching means and biasing the first locking member to its unlocked condition, whereby unlocking the lock unlatches the first locking member to release it and allow the door to be opened, the separate actuator utilised in the arrangement of WO 98/40590 can be dispensed with.

Preferably the first locking member is in the form of a rotatable claw which is engageable by said latching means. This leads to a simple and robust arrangement in which the claw is rotated by its associated biasing means during unlocking to repulse the second locking member and thereby facilitate opening of the door.

In one embodiment said latching means comprises a pivoted arm which is biased into engagement with said first locking member and is coupled by a linkage to said lock.

In a typical installation the first locking member and locking means are mounted adjacent a bottom edge of a vehicle door and the second locking member is mounted in the vehicle floor.

Other preferred features are defined in the dependent claims.

The invention also provides a vehicle having a door locking arrangement as defined above.

A preferred embodiment of the invention is described below by way of example only with reference to Figures 1 to 3 of the accompanying drawings, wherein: Figure 1 is a sketch perspective view of the bottom edge of a sliding rear door and the rear edge of the floor of a vehicle incorporating a locking arrangement in accordance with the invention; Figure 2 is a schematic elevation, partly in section (taken from the rear of the vehicle with the cover plate of the locking mechanism removed) of the locking arrangement of Figure 1 in its unlocked open condition; Figure 3 is a similar schematic elevation of the above locking arrangement in its closed locked condition; Figure 4 illustrates another lockset for a roller shutter door, including a perspective view from one side of a lock : Figure 5 is a perspective view from the other side of Figure 4 lock ; Figure 6 is a rear view of the Figure 4 lock with part of the lock housing removed.

Referring to Figure 1, the roller shutter rear door 1 of a commercial vehicle is shown with a tongue 5 projecting downwardly from its bottom edge towards a recess 3 formed in the floor 2 of the vehicle adjacent the rear edge. A U-shaped cut-out C is formed in tongue 5 and is aligned with a transverse bar 4 secured below floor level in recess 3. In this embodiment, bar 4 constitutes the"second locking member. " The outer surface of door 1 has a fixed handle H mounted on a cover plate of the locking mechanism (described befow). A Yale (RTM) pin tumbler lock barrel 6 is also set into this cover plate.

Referring now to Figure 2j the mechanism comprises a claw 8 ("the first locking member") which is mounted for rotation about axis 10 defined by a bearing mounted on tongue 5. Claw 8 is biased to rotate clockwise by a tension spring S2 connected between a fixed pin 40 carried on the door 1 and an aperture in a flange F2 extending from the claw. Figure 2 shows the claw 8 in its limit position (defined by a stop, not shown) in which a recess R2 is vertically aligned with bar 4.

An L-shaped latching arm 7 is pivoted about an axis 20 defined by a further bearing mounted on door 1 and has a projection P at the free end of its shorter limb which can ride over the arcuate periphery of claw 8. In the latched condition the projection P fits into a recess R1 of the claw. The free end of the longer limb of arm 7 is coupled by a link L to the free end of an arm 11 carried on the barrel of Yale lock 6. Latching arm 7 is biased in the anti-clockwise direction by a tension spring S1 which is connected between an aperture formed in a flange F1 on the left side of the longer limb of the arm and a fixed pin 50 mounted on door 1.

In use, as the door 1 is lowered (using fixed handle H, Figure 1) as illustrated by arrow A, recess R2 engages rod 4 as the tongue 5 enters recess 3 and this engagement rotates claw 8 anti-clockwise as illustrated by arrow B until recess R1 registers with projection P. Latching arm 7 is then rotated slightly in the anti-clockwise direction by biasing spring S1 to latch the claw 8 by engagement of the projection P in recess R1, resulting in the locked configuration illustrated in Figure 3.

Referring to Figure 3, it will be seen that claw 8 has rotated sufficiently to prevent withdrawal of the bar 4, thereby locking the tongue 5 in recess 3, i. e. locking the door shut. The door can be unlocked by inserting a key (not shown) in a keyhole 30 of lock 6 to rotate the barrel and hence arm 11 clockwise. This movement is transmitted by link L to latching arm 7 which rotates against the biasing force of spring S1 to lift projection P out of recess R1. Accordingly claw 8 is now free to rotate clockwise under the action of spring S2 to revert to the configuration shown in Figure 2, i. e. unlocking the door. This is assisted by a layer of elastomeric material 9 on floor 2 which is aligned with and compressed by the edge of door 1 and tends to spring door 1 upwardly.

Thus door 1 can be closed and latched shut with a single-handed operation using handle H (i. e. without requiring any operation of lock 6) and can also be opened with a single-handed operation simply by unlocking lock 6, the necessary upward impetus to door 1 being provided initially by elastomeric layer 9 and subsequently by tension spring S2 which causes the bottom of recess R2 to push against bar 4. This contrasts with locking devices in the marketplace which require two separate actuations and are generally inconvenient for the van driver.

Figure 4 shows a lockset including a lock 20, strike 21 and electronic control apparatus 22, 23 and 24. Figures 5 and 6 are respective further views of the lock 20. This lock is intended for use on a vehicle 100 as shown in Figure 7. The lock 20 is fitted to a roller shutter door 101 and the strike 21 lock is fitted into the floor 102 of the vehicle below the lock. The lock 20 comprises rectangular housing 25 fixed to the back of a generally rectangular steel face plate 26 having four holes near the respective corners by which the plate 26 can be fixed by bolts 103 (Figure 7) to the lower slat 104 of the roller shutter door 101. A relatively thin decorative trim plate 27 is fitted over the plate 26 using the bolts 103 or, alternatively, the decorative trim plate 27 could be fixed by some other means, e. g. adhesive or small chrome screws, so as to cover the heads of bolts 103. The housing 25 and face plate 26 have matching projecting tongues 28 and 29 respectively which extend down from lower portions of the housing and face plate and which have portions defining matching slots 30 and 31 extending up from the lower edges of the tongues 28 and 29. Near the mouths of the slots 30 and 31, the slots taper outwards while the inner ends 32 of the slots are rounded.

The face plate 26 has a laterially extending flange 33 projecting from the lower edge 34 of the face plate 21, i. e. extending away from the housing 25. Two further flanges 35 and 36 respectively extend from inner portions of the lower edge 34 of the face plate 26 and from the lower edge and sides of the tongue 28 in the direction towards the tongue 29 and into contact therewith. The flanges 35 and 36 lie each side of the slot 30 in the face plate 26, i. e. as to leave the mouth of the slots 30 clear. A grab handle 40 is fixed to face late 26 and trim plate 27.

A pin tumbler lock barrel 50 extends through an aperture 51 in the face and trim plate with the keyhole accessible for key entry. Also, a mechanical counter 52 is provided with the numbers viewable at the trim plate side. This counters the number of operations of the lock.

The strike 21 comprises a strike plate 60 fixed by bolts (not shown) engaged through holes 61 to the floor 101 of the vehicle 100.

The strike plate 60 has an elongate slot 62 for receiving the tongues 28 and 29. Beneath the slot 62, there is a housing 63 of which the sides support a transverse bar 64. The bar can move in the length direction of the slot 62 to a limited extent.

The lock mechanism comprises a locking claw 70 made up of three plates sandwiched together and welded one to another. The central plate has a projecting portion 71 with a hole therein. The three plates are otherwise the same. A hole 72 is formed through the plates and an oil impregnated bronze bush 73 is inserted in the hole. By the bush 73, the claw is mounted on a spindle 74 fixed to the plate 26. Diametrically opposite the projection 71, the claw 71 is formed with the claw aperture 75. Between the claw aperture 75 and the projecting 71, there is formed a latching recess 76 and a stop depression 77.

A latching member 80 which, like the claw 70, is made up of three sandwiched together plates (not separately shown) has a bore with an oil impregnated bush 81 and fitted onto another spindle 82 fixed to the plate 26 so that the latching member can turn about the axis of the spindle 82. The member 80 has a catch portion 83 at one end able to engage the latching recess 76 as shown. Also, the latching member 80 can be lifted from the position shown in Figure 6 and then the claw 70 can turn about the axis of spindle 74. Near the other end of latching member 80, there is a lug 84 coupled by tension spring 85 to a lug fixed to plate 26. Another tension spring 86 is connected between lug 85 and the projection 71.

At the other end of latching member 80, there is a lever portion 87 which extends through a slot 88 in the end of the housing 25. This provides an internal release lever for enabling someone inside the vehicle to release the door lock manually. Also at the end of the latching member 80, there is a rotable collar 89 fixed by a screw 90 and in engagement with a camming member 200 fixed by nut 91 to the end of the cylinder 92 of the lock barrel 50.

The armature 93 of an electrical solenoid actuator 94 is coupled to the latching member 80 by staple 94.

The operating lever 95 of the counter 52 is coupled via tension spring 96 to the projection 71.

Solenoid actuator 94 is electrically coupled to a microprocessor-based control circuit 22 and a receiver 23, for example an infra-red receiver, for receiving signals from a remote transmitter 24, for example a key with a battery powered or passive infra-red transmitter.

The control circuit could be mounted inside the housing 25 or elsewhere in the vehicle while the receiver could also be positioned in a suitable place in the vehicle or possible exposed at the back of the plate 26.

The operation of the lock is similar to that of the lock of Figures 1 to 3. When the door is slammed down on the floor of the vehicle, the slot 39 engages over bar 64, the claw aperture being open, i. e. downwards, at this time. Bar 64 engages the claw 70 and rotates it to the position shown in Figure 6 and it is latched there by latching member 80. As claw 70 rotates, it adds a count of one to the number shown by counter 52. Alternatively, the counter may be incremented when the door is opened as preferred, depending upon the selector operation of the counter.

When the lock barrel cylinder is turned, camming member 200 turns also and engages and releases the claw 70 by moving latching member 80 downwards. Similarly, solenoid actuator 94 can pull the latching member 80 down and also release the claw 70.

The solenoid actuator 94 and counter 52 could be omitted if desired or replaced by like equivalent mechanisms or coupled in alternative ways. For example, solenoid 94 could be replaced by a motor and counter 52 could be replaced by an electrical or electronic counter mechanism. Housing 25 is fixed to plate 26 by nuts, bolts and spacers (not shown) extending through holes 305.

Flange 33 has two spaced holes 300 formed therein and these match two further holes 301 in the striker plate 60. A housing is formed beneath the holes 301. When the door is closed, a flexible elongate member, for example a self-locking plastics cable tie, can be threaded through the holes to show that the door has not been opened.