GB2424445A

GB2424445A - Key operated latch particularly suited to an automotive boot compartment

Info

Publication number: GB2424445A
Application number: GB0506021A
Authority: GB
Inventors: Sidney Edward Fisher
Original assignee: ArvinMeritor Light Vehicle Systems France SA
Current assignee: Inteva Products France SAS
Priority date: 2005-03-24
Filing date: 2005-03-24
Publication date: 2006-09-27
Also published as: GB0506021D0

Abstract

A latch assembly 10, comprising a latch mechanism 14 including a latch bolt 30 and a pawl 40 for releaseably retaining the latch bolt 30 in a closed position; a lock mechanism 12 connected to the pawl having a key hole for insertion of a key which is operable to move the pawl 40, the latch assembly 10 having: a first condition when the latch bolt 30 is releasably retained by the pawl 40 in the closed position and the key is removable; a second condition when the latch bolt 30 is in an open position and the key is not removable and subsequent movement of the latch bolt 30 to the closed position causes the latch bolt 30 to be releasably retained by the pawl 40; and a third condition where the latch bolt 30 is in the open position and the key is removable and subsequent movement of the latch bolt 30 to the closed position will not cause it to be releasably retained by the pawl 40. Particularly suited to a vehicle boot door and prevents car keys being locked in the trunk.

Description

The current invention relates to vehicle boot lids and tailgates, and in

particular but not exclusively, to a device for preventing the locking of a boot key within the boot compartment of a passenger vehicle.

Most modern cars are fitted with a boot (sometimes referred to as a trunk) which is accessible from the exterior of the car. Access is provided in a number of different ways.

For example, hatchbacks have a tailgate which is hinged near the roof line of the vehicle and which includes the rear windscreen. This provides a boot compartment which is accessible from the passenger compartment of the vehicle. Alternatively, a saloon has a boot lid hinged below the rear windscreen to provide a boot compartment separate from the passenger compartment of the vehicle. Estate cars are similar to hatchbacks in that they have a tailgate hinged near the roof line of the vehicle with a roof line which is extended rearwards to increase load carrying capacity of the vehicle.

Irrespective of the type of boot, a common feature is that they are all lockable and unlockable from the exterior of the vehicle. Whilst most modem cars allow remote locking/unlocking of the boot, it is usual for the boot to be lockable/unlockable with a conventional key.

For ease of reference the term "boot lid" is used to refer to the tailgate of a hatchback, the conventional boot lid of a saloon, or any other form of boot closure. The term "boot" is construed accordingly.

Whilst the manual locking and unlocking of the boot can be a useful feature, it also presents a potential problem to the user. Current boot latches employ an antitheft feature which prevents the boot latch from remaining unlocked following the unlocking and opening of the boot (when the rest of the vehicle doors are locked). This is typically achieved in one of two ways. Firstly, the latch automatically relocks after the removal of the key from the barrel. Secondly, the key can only be removed from the key barrel once the key has been rotated back to the locked position. The boot lid then locks automatically when subsequently closed by the user.

However, this feature presents a problem where the key has been accidentally left within the boot compartment prior to the closing of the boot as the key can easily become locked in the boot. This is a problem often experienced by users when loading items into the boot compartment.

It is an object of the cunent invention to provide a latch which mitigates the above problems.

According to the invention there is provided a latch assembly comprising:a latch mechanism including a latch bolt having a closed position and an open position and a pawl for releaseably retaining the latch bolt in the closed position, the latch assembly further comprising a lock mechanism connected to the pawl and having a key hole for insertion of a key which is operable to move the pawl, the latch assembly having a first condition when the latch bolt is releasably retained by the pawl in the closed position and the key is removable from the key hole, a second condition when the latch bolt is in the open position and the key is not removable from the key hole and subsequent movement of the latch bolt to the closed position causes the latch bolt to be releasably retained by the pawl, and a third condition where the latch bolt is in the open position and the key is removable from the key hole and subsequent movement of the latch bolt to the closed position will not cause it to be releasably retained by the pawl.

This arrangement is advantageous in that the key cannot be locked in the boot following the opening of the boot lid. Operation of the lock mechanism by the key to release the latch bolt and thereby open the latch assembly moves the pawl to its second position. With the pawl in this position the key is retained by the lock mechanism. The key may only be released in one of two ways. Firstly, the boot lid can be closed which allows the pawl to return to its first position. Secondly, the key may be turned in the lock mechanism to move the pawl to its third position in which it is not able to engage the latch bolt when the boot lid is subsequently closed. The key can then be removed from the lock mechanism with the pawl retained in its third position. This allows the boot lid to be shut without latching the latch assembly. The boot can subsequently be locked by reinserting the key and turning the lock mechanism to move the pawl back to its first position.

The invention will now be described by way of example only and with reference to the following figures in which: Figure 1 is a schematic view of the latch assembly of the current invention; Figure 2 is a schematic view of the latch assembly of figure 1 in the closed condition; Figure 2A is a schematic view of the key barrel of figure 2 shown in the first position; Figure 3 is a schematic view of the latch assembly of figure 1 in the open condition; Figure 3A is a schematic view of the key barrel of figure 3 shown in the second position; Figure 4 is a schematic view of the latch assembly of figure 1 in the open condition with the key removed; Figure 4A is a schematic view of the key barrel of figure 4 shown in the third position; Figure 5 shows an alternative embodiment of latch assembly according to the present invention.

With reference to figure 1 the latch assembly indicated generally at 10 comprises a lock mechanism 12 and a latch mechanism 14 mounted on a vehicle boot lid shown schematically at 18. The lock mechanism 12 is connected to the latch mechanism 14 by way of a connecting rod 16.

In use, the latch assembly 10 is mounted on the vehicle boot lid so as to allow an associated striker (mounted on the body of the vehicle) to engage the latch mechanism 14 at the shut face of the boot lid 18.

The latch mechanism 14 has a latch bolt 30 rotatable about a pivot 32. The latch bolt 30 includes a mouth 34 for receiving a striker 35 (shown by dotted line in Figure 1 only), and a closure face 36 arranged at the periphery of the mouth 34. Arranged to releasably engage with the latch bolt 30 is a pawl 40 which is rotatably mounted on a pivot 42. The pawl includes a first arm 44 which includes a pawl tooth 45 for releasably engaging the latch bolt 30, and a second arm 46 which is attached to a second end 28 of the connecting rod 16.

The pawl 40 is biased in an anticlockwise direction by a spring 33. The spring 33 has a first end which acts on the first arm 44 of the pawl 40, and second arm which act against a stop 47 which is mounted on the latch chassis (see below).

The latch bolt 30 is biased for rotation in a clockwise direction by a spring not shown which acts between the latch bolt 30 and a latch chassis 15 (shown schematically in figure 1 only) in a known manner.

With reference to Figures 2, 3 and 4, the latch bolt 30 has a closed position (Figure 2) and an open position (Figures 3 and 4). The pawl 40 has a first position (Figure 2), a second position (Figure 3) and a third position (Figure 4). It will be appreciated that the first position of the pawl 40 corresponds to the closed position in the latch bolt 30 and that the second and third positions of the pawl 40 correspond to an open position in the latch bolt 30.

Referring again to figure 1, the lock mechanism 12 has a key barrel 20 which has a key slot (also known as a key hole) 22 for receiving a key 23 (shown in Figure 3 only). Attached to the key barrel 20 and rotatable therewith is a lock lever 24 which is connected to a first end 26 of the connecting rod 16.

in the present invention latching/unlatching occurs by the movement of the latch bolt between its open and closed positions. This allows the latch mechanism 14 to open and close and thereby allows the latch assembly 10 to latch and unlatch. The lock mechanism acts on the latch mechanism so as to facilitate unlatching the latch mechanism.

Referring now to figure 2 to 4 and 2A to 4A, the key 23 is capable of rotating the key barrel between first, second and third positions which correspond to the first, second and third positions of the pawl 40. The key barrel 20 defines a first stop to prevent the barrel from rotating anticlockwise past the first position. This prevents undue pressure being applied to the latch bolt 30 by the pawl 40. The key barrel has a second stop to prevent the barrel rotating past the third position.

With the key barrel 20 in its first position (figure 2, 2A) the latch assembly is closed.

When the key barrel 20 is in its second position (figures 3, 3A) the latch assembly is open, but remains closable on engagement of the latch bolt 30 with the associated striker. When the key barrel 20 is in its third position (figures 4, 4A) the latch is open, but is not closable without moving the pawl back to its second position by rotation of the key barrel 20 to its second position.

Figures 2 and 2A show the latch bolt 30 in its closed position and the key barrel 20 and pawl 40 in their first positions. Consequently, the latch assembly is closed.

In use, the latch assembly can be opened by rotation of the key barrel 20, which in turn operates the pawl 40 by way of the connecting rod 16 as follows.

Starting from the position shown in figure 1, the operator inserts the key into the key slot and then rotates the key 23 clockwise thereby rotating the key barrel until the key barrel 20 hits a stop (not shown), i.e. the components move to the position shown in figures 4 and 4A. The action of the connecting rod 16 upon rotation of the key barrel 20 causes the pawl to rotate in a clockwise direction about the pivot 42. This causes the pawl tooth 45 to disengage from the closure surface 36 and thereby release the latch bolt 30. The striker is then released from the mouth 34 of the latch bolt 30 which allows the opening of the latch assembly.

Upon subsequent releasing of the key, the rotationally biased pawl 40 drives the key barrel back to its second position (i.e. the position shown in figures 3 and 3A) by way of the connecting rod 16. In this position the pawl tooth 45 is urged against the outer surface of the latch bolt 30 by way of the spring 33 (see figure 1). Significantly, the key cannot be removed from the key slot when the components are in the figure 3 position.

To re-latch the latch assembly, the operator closes the boot lid which causes the striker (not shown in Figures 2 to 4 for clarity) to be driven into the mouth 34 of the latch bolt 30. This causes the latch bolt to rotate anticlockwise in direction A against the rotational bias of the latch bolt spring (not shown), which rotation drives the closure face 36 past the pawl tooth 45. The rotational bias of the latch bolt 30 causes the closure face 36 to abut the first arm 44 of the pawl which itself is rotationally biased towards the mouth 34 of the latch bolt 30 by the spring 33. The latch assembly is thereby retained in the closed condition. Thus the components are returned to the position shown in figures 2 and 2A.

As mentioned above, the key 23 can be removed and inserted freely into and out of the key slot 22 when the latch bolt 30 is in the closed position and the key barrel in the first position, as shown in figures 2 and 2A. However, the key barrel 20 retains the key within the key slot 22 when the key barrel 20 is between the first and third position. This prevents the key 23 being removed from the key barrel 20 with the latch assembly in a condition in which it can be latched.

However, occasionally it can be convenient to remove the key from the key barrel 20 with the latch still in an open condition. This scenario is provided for by the present invention as follows. The latch assembly is opened, as described above, by turning the key to move the key barrel to its third positions as shown in figures 4 and 4A. However, rather than releasing the key and allowing the components to move to the figure 3 position under the bias of spring 33, the operator simply removes the key from the key slot whilst the components are in the figure 4 position. Note that in this position the pawl tooth 45 is fully disengaged from the latch bolt 30. The key barrel 20 is specifically configured to remain in the figure 4 position upon removal of the key 23 and hence the pawl tooth 45 remains disengaged from the latch bolt 30.

As a result, even if the keys were removed and accidentally left in the boot, closure of the boot lid would not lead to closure of the latch assembly since the pawl tooth 45 is unable to engage the closure surface 36 of the latch bolt 30 in order to retain the latch bolt in the closed position.

Thus, the latch assembly is closeable in the open condition as shown in figure 3, but the key cannot be removed from the key barrel with the latch in this condition. Moving the key barrel to the position shown in figure 4, allows the key to be removed, but prevents the latch from closing because the pawl is held out of engagement from the latch bolt. In this case the act of removing the key from the key slot causes the key barrel to lock in position and hence prevent the lock lever from rotating.

To return the latch assembly to a latchable condition, the key 23 is inserted back into the key slot 22 and the key barrel is rotated back to the second position (as shown in figure 2) under the action of the rotationally biased pawl 40.

To close the latch assembly the operator closes the boot lid which causes the striker to re-engage the latch bolt 30. The latch bolt 30 is rotated in an ariticlockwise direction under the action of the striker to its closed position as shown in figure 2, and the pawl tooth 45 rotates in an anticlockwise direction to engage the closure surface 36.

in figure 5, a second embodiment of latch assembly 100 is mounted on a vehicle body which is shown schematically at 118. In this embodiment a striker, which is not shown for clarity, is mounted on a vehicle boot lid. Further components are numbered in common with the first embodiment and the mode of operation of this embodiment is essentially identical to the first embodiment.

It is conceivable within the scope of the invention that the connecting rod may be replaced by a similar connection device such as a bowden cable or pulley system.

It is also conceivable that the coil spring 33 may be replaced by an alternative form of biasing means.

In a further embodiment a motor, such as an electric motor may be configured so as to unlatch the latch in the absence of key operation of the unlocking lever. Under such circumstances a lost motion connection can be provided between pawl 40 and the lock mechanism to enable the pawl to be moved by the motor whilst the lock mechanism remains stationary. Typically, the motor may be actuated by operation of a remote unlocking system, such as a central locking system. Alternatively, or additionally, the motor may be operated by a switch situated in the passenger compartment, typically proximate the drivers seat.

Claims

Claims 1. A latch assembly comprising:- a latch mechanism including a

latch bolt having a closed position and an open position and a pawl for releaseably retaining the latch bolt in the closed position, the latch assembly further comprising a lock mechanism connected to the pawl and having a key hole for insertion of a key which is operable to move the pawl, the latch assembly having a first condition when the latch bolt is releasably retained by the pawl in the closed position and the key is removable from the key hole, a second condition when the latch bolt is in the open position and the key is not removable from the key hole and subsequent movement of the latch bolt to the closed position causes the latch bolt to be releasably retained by the pawl, and a third condition where the latch bolt is in the open position and the key is removable from the key hole and subsequent movement of the latch bolt to the closed position will not cause it to he releasably retained by the paw!.
2. The latch assembly of claim 1 wherein the lock mechanism includes a key barrel for receiving the key.
3. The latch assembly of claim 2 wherein the key barrel operates a lever to move the pawl in use.
4. The latch assembly of claim 3 wherein the lever and the pawl are connected by a rigid link.
5. The latch assembly of claim 3 wherein the lever and the paw! are connected by a Bowden cable.
6. The latch assembly of any one of claims 2 to 5 wherein the key barrel has a first stop to prevent the pawl rotating past its first position.
7. The latch assembly of any one of claims 2 to 6 wherein the key barrel has a second stop to prevent the pawl rotating past its third position.
8. The latch assembly of any one of claims 2 to 7 including means for preventing rotation of the key barrel when the key is removed from the key hole when the latch assembly is in the first andlor third conditions.
9. The latch assembly of any preceding claim wherein the pawl is urged against an outer profile of latch bolt when the paw! is in its second position.