MOTOR VEHICLE LATCHING ASSEMBLY

Abstract: A latching assembly for releasably retaining a striker (2) is disclosed in which the assembly comprises a safety hook (4) biased for rotational movement to a closed position through an ajar position from an open position, a catch claw (6) pivotally biased for rotational movement from a first position in which the striker (2) is constrained from moving to a second position in which the striker (2) is driven to a predetermined position, and a release pawl (8) biased for rotational movement between a first position in which the catch claw (6) is held in the first position and a second position in which the catch claw (6) is released to move to the second catch claw position, characterised in that the catch claw (6) and the safety hook (4) about one another in such a manner that, when the catch claw (6) is moved to its second position, the safety hook (4) is moved to its ajar position and the striker is held in a partially restrained position by the safety hook (4).

Description: MOTOR VEHICLE LATCHING ASSEMBLY The present invention relates to a motor vehicle assembly, and in particular to a latching assembly for securing, for example, a bonnet to a motor vehicle body. A number of such latching assemblies are known. Such units typically allow a vehicle covering assembly to adopt one of three positions; locked, ajar or latched; and open. One prior art latching assembly is disclosed in US 5,738,393 in which a safety hook is released by a second movement of a release pawl. In order to achieve this, a lost motion mechanism is provided between a safety hook, a catch claw and the release pawl. It is known to provide a covering assembly, such as a bonnet, which includes one or more lighting units. When the bonnet is in a closed position, such as is normal when the vehicle is being driven, any actuated lighting units are directed at the driving surface in accordance with any appropriate legislative requirements. However, if access to the vehicle engine compartment is required such that it requires the release of the bonnet, the latching assembly will place the bonnet in a latched or ajar position, effectively raising the lighting units. It is a problem that many latching units will raise the bonnet such that any attached actuated lighting units are raised beyond the limit of the appropriate legislative requirements, and in particular the actuated lighting units will be directed at and dazzle the drivers of oncoming vehicles. This is clearly undesirable. While some known latching mechanisms are believed to address this problem, such units tend to be mechanically complex leading to expense in assembly of such latching units and subsequent incorporation into a motor vehicle. Further due to the number of parts, such assemblies are unnecessarily heavy. This in turn discourages the use of such vehicle bonnet arrangements. The present invention has as an advantage that it contains relatively few moving parts and is comparatively easy to assemble. According to a first aspect of the present invention in a latching assembly for releasably retaining a striker, the assembly comprises a safety hook biased for rotational movement to a closed position through an ajar position from an open position, a catch claw pivotally biased for rotational movement from a first position in which the striker is constrained from moving to a second position in which the striker is driven to a predetermined position, and a release pawl biased for rotational movement between a first position in which the catch claw is held in the first position and a second position in which the catch claw is released to move to the second catch claw position, characterised in that the catch claw and the safety hook abut one another in such a manner that the striker is held in a partially restrained position. This feature also acts to maintain the safety hook release presenter in its accessible position. Preferably, the safety hook comprises a first surface to constrain movement of the striker and an abutment surface, the catch claw comprises a recess to restrain movement of the striker, a surface to drive the striker, a first lug including an outer surface and an abutment surface, and the release pawl comprises a recess for engagement with the first lug of the catch claw, a nose and a radially extending member. Preferably, in a closed condition of the assembly, the safety hook is in the closed position such that a curved surface of the safety hook overlies the striker, the catch claw is in the first position such that the recess constrains the striker and the catch claw first lug engages with the release pawl recess, in an ajar condition of the assembly the safety hook is in the ajar position such that the curved surface of the safety hook overlies the striker, the release pawl is moved from the first position such that the catch claw is released and the catch claw moves to the second position such that the drive surface of the catch claw drives the striker upwards, the catch claw first lug outer surface abuts the release pawl nose and the safety hook abutment surface and the catch claw abutment surface abut one another, and in an open condition the safety hook is moved to the open position to allow removal of the striker from the assembly. The invention will now be described, by way of example only, with reference to the accompanying drawings, in which; Figure 1 shows a side sectional view of a latching assembly according to the present invention in a first, closed position; Figure 2 shows a side sectional view of the latching assembly of Figure 1 in a second, latched or ajar position; Figure 3 shows a side sectional view of the latching assembly of Figure 1 in a third, open position; and Figure 4 shows and exploded view of a latching assembly according to the present invention. Referring first to Figure 1, there is shown a side sectional view of a latching assembly according to the present invention in a first position. The latching assembly comprises a striker 2, a pivotally mounted safety hook 4, a pivotally mounted catch claw 6, and a pivotally mounted release pawl 8. The striker 2 comprises a loop or hook mounted to one of a vehicle bonnet and a vehicle body (not shown). That portion of the striker which engages with other parts of the latching assembly is subsequently referred to as a striker pin. Preferably, the striker is mounted to the vehicle bonnet. The remainder of the latching assembly is mounted to the other of the vehicle bonnet and the vehicle body, typically the vehicle body. The safety hook 4 and the catch claw 6 are mounted between a first lower flat bracket 10 and a second top-hat shaped bracket 12. The release pawl 8 is mounted to the second bracket 12. The second bracket is shown in part-section and outline only in Figures 1 to 3 for purposes of clarity. The first bracket is provided with a spigot 14 on which the safety hook is mounted for rotation about a first axis. A bushing may be provided between the spigot and the safety hook. The spigot is mounted generally centrally on the first bracket. The spigot may be mounted to the bracket according to any suitable means. The safety hook 4 is biased to rotate in an anticlockwise manner as shown in the Figures. Conveniently the safety hook is biased by spring means 5 (Figure 4). The safety hook comprises first and second safety hook members. The first safety hook member 16 extends radially from the first axis. The first safety hook member extends from the spigot such that it extends beyond the first and second brackets. The first safety hook member 16 is attached at a remote end 18 to a first end 20 of a safety hook release presenter 22. The second safety hook member 24 is generally hook shaped defined by an upper surface 30 and a curved surface 26 separated by a nose portion 28. The second safety hook member 24 further includes a first abutment surface 32. The curved surface 26 in use is adapted to constrain movement of the striker pin. It will be understood that the safety hook 4 extends in a first plane substantially parallel to the first bracket. The safety hook release presenter 22 is restrained by means (not shown) to move back and forth only along a single direction. The safety hook release presenter is provided at an end 34 remote from the safety hook with means to impart movement to the safety hook release presenter. Conveniently, such means may take the form of a handle 36 to be gripped by a user. The second upper bracket 12 is provided on its raised portion with a first spigot 38 and a second spigot 40. The first spigot 38 and the second spigot 40 may be mounted to the second upper bracket by any suitable means. The catch claw 6 is mounted on the first spigot 38 on the second bracket for rotation about a second axis. A bushing may be provided between the spigot 38 and the catch claw 6. The catch claw 6 is biased to rotate in an anti-clockwise direction as shown in the Figures. This may conveniently be achieved by the use of a double torsion spring 7 (Figure 4). The release pawl 8 is mounted on the second spigot 40 on the second bracket for rotation about a third axis. A bushing may be provided between the spigot 40 and the release pawl 8. The release pawl 8 is preferably biased to remain in the position shown in Figure 1. This may conveniently be achieved by the use of spring means 9 (Figure 4). The catch claw 6 comprises three catch claw members each extending radially from the second axis. A first catch claw member 42 is generally hook shaped and includes a recess 48 to restrain movement of the striker pin. A second catch claw member 44 comprises a generally T-shaped member, comprising a first lug 51 and a second lug 53 extending outwardly from a member extending radially of the spigot. An outer surface 49 extends between the first and second lugs 51,53. A driving surface 50 is formed between the first and second catch claw members. A third catch claw member 46 comprises a radially extending member incorporating an abutment surface 52. It will be understood that the catch claw extends in a second plane substantially parallel to the first plane containing the safety hook 4. The first abutment surface 32 of the safety hook extends at least as far as the second plane. In an alternative embodiment (not illustrated) the abutment surface of the catch claw may extend downwards into the first plane to abut the abutment surface of the safety hook. In a further alternative embodiment (not illustrated) each of the catch claw abutment surface and the safety hook abutment surfaces may extend out of their respective planes such that they will abut one another upon suitable rotation of the catch claw and safety hook respectively. The release pawl 8 comprises two members extending radially from the third axis. A first release pawl member 54 extends radially from the second spigot 40, is generally hook shaped and includes a recessed surface 58 and a nose portion 60. The second release pawl member 56 extends from the spigot such that it extends beyond the first and second brackets. It will be understood that the release pawl 8 extends in the second plane as the catch claw 6. When a bonnet is in a closed position and the bonnet is secured to a motor vehicle body, the latching assembly is in the closed position shown in Figure 1. The striker pin is constrained from movement by the recess 48 of the first catch claw member 42, while the hook shaped member 24 of the safety hook is seated upon the striker pin. At the same time first lug 51 of the second catch claw member 44 is retained within the recessed surface 58 of the first release pawl member 54 to prevent an anti clockwise rotation of the catch claw. When it is desired to open the bonnet, the release pawl 8 is actuated. The release pawl 8 is conveniently actuated by control means located within a passenger cell of the motor vehicle, but may also be actuated in any other suitable manner. When actuated, the second release pawl member 56 is urged to in a clockwise rotational movement around the spigot 40 as shown in the drawings by arrow A. The first release pawl member 54 is moved in a clockwise rotational movement around spigot 40, thereby releasing the first lug 51 of the second catch claw member 44 from the release pawl recessed surface 58. The catch claw is now free to rotate in an anti clockwise manner, as shown by arrow B. The release pawl is held against the release pawl biasing means by the outer surface 49 of the second catch claw member 44 abutting the nose portion 60 of the release pawl and is so unable to return to the closed position. The driving surface 50 between the first and second catch claw members pushes the striker pin upwards. This movement of the striker pin raises the curved surface 26 of the second safety hook member against the force of the biasing means. This has the effect of causing the safety hook 4 to rotate clockwise about the first spigot 14 as shown by arrow C, moving the remote end 18 of the first safety hook member 16 clockwise about spigot 14 as shown in Figure 2. This in turn displaces the safety hook release presenter 22 forwards to the left as shown in Figure 2. As the catch claw 6 rotates anticlockwise and the safety hook 4 is urged in an clockwise direction, the first abutment surface 32 of the safety hook and the abutment surface 52 of the catch claw come into abutment with one another. This prevents anticlockwise rotation of the safety hook 4. The catch claw 6 is prevented from rotating further by the presence of a tab (not shown for reasons of clarity) extending from the upper bracket 12. Also, in this position, the second member 44 of the catch claw abuts the nose portion 60 of the release pawl 8 to prevent further movement of the release pawl as noted above. In this position, the striker pin cannot be removed from the latching assembly since it is still restrained by the curved surface 26 of the first safety hook member 16. By altering the precise geometry of the driving surface 50 or the curved surface 26 or both the opening of the bonnet may be carefully controlled. To open the bonnet further, a user imparts a leftward movement to the safety hook release presenter 22 shown in the Figures as shown by arrow D, for example by pulling the handle 36. This has the effect of rotating the first safety hook member 16 further clockwise about the spigot 14 as shown by arrow E (Figure 3). This pivoting of the safety hook 4 moves the second safety hook member 24 clockwise as shown in the drawings and away from the striker pin. As a result, the striker pin is free to be moved from the latching assembly in the direction of arrow F. When the safety hook release presenter 22 is released the safety hook biasing means returns the safety hook release presenter 22 to the latched or ajar position shown in Figure 2. Spring means 5 urges the safety hook 4 anticlockwise, causing abutment surface 32 to rotate clockwise into contact with the abutment surface 52 of the catch claw 6 When the bonnet is to be closed, the striker pin is urged towards the rest of the latching assembly. Firstly, the striker pin strikes the upper surface 30 of the safety hook 4. This urges the safety hook 4 in an clockwise direction against the safety hook biasing means until the striker pin has passed the nose portion 28 of the safety hook. The safety hook is then urged over the striker pin such that the curved surface 26 passes over the striker pin. The striker pin next strikes the driving surface 50 of the catch claw. The catch claw 6 is then driven in an anticlockwise direction against the release pawl 8, until the striker pin engages with the recess 48 in the catch claw. This has the effect of urging the release pawl 8 in a n anticlockwise direction, thereby causing the second member 44 of the catch claw to return to the release pawl recessed surface 60. Once this has been completed, it can be seen that the latching assembly has returned to the locked position illustrated in Figure 1.

Claims: CLAIMS 1. A latching assembly for releasably retaining a striker, the assembly comprising a safety hook biased for rotational movement to a closed position through an ajar position from an open position, a catch claw pivotally biased for rotational movement from a first position in which the striker is constrained from moving to a second position in which the striker is driven to a predetermined position, and a release pawl biased for rotational movement between a first position in which the catch claw is held in the first position and a second position in which the catch claw is released to move to the second catch claw position, characterised in that the catch claw and the safety hook abut one another in such a manner that the striker is held in a partially restrained position. 2. A latching assembly according to claim 1, characterised in that the safety hook comprises a first surface to constrain movement of the striker and an abutment surface, the catch claw comprises a recess to restrain movement of the striker, a surface to drive the striker, a first lug including an outer surface and an abutment surface, and the release pawl comprises a recess for engagement with the first lug of the catch claw, a nose and a radially extending member. 3. A latching assembly according to claim 2, characterised in that in a closed condition of the assembly, the safety hook is in the closed position such that a curved surface of the safety hook overlies the striker, the catch claw is in the first position such that the recess constrains the striker and the catch claw first lug engages with the release pawl recess, in an ajar condition of the assembly the safety hook is in the ajar position such that the curved surface of the safety hook overlies the striker, the release pawl is moved from the first position such that the catch claw is released and the catch claw moves to the second position such that the drive surface of the catch claw drives the striker upwards, the catch claw first lug outer surface abuts the release pawl nose and the safety hook abutment surface and the catch claw abutment surface abut one another, and in an open condition the safety hook is moved to the open position to allow removal of the striker from the assembly. 4. A latching assembly according to any previous claim, characterised in that the safety hook is mounted in a first plane and the catch claw and the release pawl are mounted in a second plane. 5. A latching assembly according to any previous claim, characterised in that the safety hook is mounted to a first plate and the catch claw and the release pawl are mounted to a second plate. 6. A latching assembly according to claim 2 or claim 3, characterised in that the safety hook is mounted in a first plane and the catch claw and the release pawl are mounted in a second plane and in that at least one of the abutment surfaces extends from one of the first and second planes towards the other of the first and second planes. 7. A latching assembly according to claim 6, characterised in that the safety hook abutment surface extends from the first plane at least as far as the second plane. 8. A latching assembly according to claim 6, characterised in that the catch claw abutment surface extends from the second plane at least as far as the first plane. . A latching assembly according to any previous claim, characterised in that the assembly further comprises a release presenter connected to the safety hook. 10. A latching assembly according to claim 9, characterised in that the release presenter includes a handle at one end. 11. A latching assembly substantially as described herein with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings. 12. A motor vehicle including a bonnet assembly secured to a motor vehicle body by a latching mechanism according to any previous claim.

Inventors: CUTLER DAVID ROBERT, CUTLER, DAVID, ROBERT
Applicants: BAYERISCHE MOTOREN WERKE AG, CUTLER DAVID ROBERT, BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT, CUTLER, DAVID, ROBERT
Application year: 2000
Main classification: E05B65
IPC codes: E05B65