LATCH

Abstract: A latch (10) including bolt (8) moveable between a latched position at which it is capable of retaining a striker (9) in an engaged position and an unlatched position at which at the striker is free to move between the engaged position and a remote position and a first retaining means (18) moveable between a retaining position at which it retains the latch bolt in its latched position and a released position at which it releases the latch bolt from its latched position and a second retaining means (16) for releasably retaining the first retaining means in its released position following unlatching of the latch, the second retaining means further retaining the first retaining means in its released position following movement of a striker from the remote position (R) to the engaged position (E).

Description: LATCH The present invention relates to latch mechanisms and - in particular latch mechanisms for securing boot lids (doors) of automobiles. Latches for securing boot lids in a closed position are known. Typically when the boot lid is slammed shut the latch will retain the boot lid in a closed position. However instances have been recorded where people in particular children have climbed into a boot and slammed the boot lid closed whilst inside the boot, and have then been unable to exist the boot. This is clearly a safety hazard. An object of the present invention is to provide a latch in which accidental trapping of children is less likely to occur. Thus according to the present invention there is provided a latch including a latch bolt moveable between a latched position at which it is capable of retaining a striker in an engaged position and an unlatched position at which at striker is free to move between the engaged position and a remote position and a first retaining means moveable between a retaining position at which it retains the latch bolt in its latched position and a released position at which it releases the latch bolt from its latched position and a second retaining means for releasably retaining the first retaining means in its released position following unlatching of the latch, the second retaining means further retaining the first retaining means in its released position following movement of a striker from the remote position to the engaged position. In some embodiments the second retaining means can be temporarily retained in a position at which it releases the first retaining means. This allows the second retaining means to be overridden and would typically be used when there is a reduced likelihood of trapping children, such as on a car owned by a family having no young children. The invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 i a view of a latch assembly according to the present invention; Figure 1 A is a view of a pawl in a first retaining position, a pawl retainer in a first released position, and fixed structure of the latch assembly of figure 1 ; Figure 2 is an isometric view of figure 1 shown with some of the fixed structure removed for clarity, Figures 3 and 4 correspond to figures 1A and 2 with the pawl in a second released position and the pawl retainer in a second retaining position, Figures 5 and 6 correspond to figures 1A and 2 with the pawl in the first retaining position and the pawl retainer in a third position; Figure 7 shows the pawl retainer in isolation for clarity ; and Figures 8,9 and 10 show schematic views of the pawl retainer in a first released position, a second retaining position, and a third position respectively. With reference to the figures there is shown a latch assembly 10 (see figure 1) secured to a boot lid 15. The latch assembly includes a latch housing 13 having a latch mouth 11. Various components are contained within the latch housing including a latch bolt in the form of a latch claw 8 being rotatable about latch claw pivot 12, a first retaining means in the form of a pawl 18 (see figure 1A) rotatable in a general plane P2 about pawl pivot 14 and a second retaining means in the form of a pawl retainer 16. With the boot lid in the open postion. a striker pin, fixed to the body of the vehicle, is at a remote position R relative to the latch assembly 10. As the boot lid is closed the striker pin 9 moves from the remote position and enters latch mouth 1 1 and adopts an engaged position E where it is retained by the claw with the pawl acting to retain the claw in its first latched position. Movement of the pawl from its first raining position to its second released position allows the claw to move from its first latched position to its second unlatched position thus releasing the boot lid for opening. The claw is biased towards its second unlatched position by a bias means (not shown). Pawl 18 includes an annular portion 19 having first arm 20, second arm 21, and third arm 22 projecting therefrom. A resilient means biases the pawl 18 in a clockwise direction as shown in figure 1A. Third arm 22 releasably engages the claw to releasably retain it in its first latched position. Second arm 21 is acted upon by a lever (not shown) to move the pawl from its first retaining position (figure 1A) to its second released position (figure 3). First arm 20 co-operates with the pawl retainer 16 as described below. The pawl retainer 16 includes a cylindrical portion 26 having a planar portion 27 situated part way along the cylindrical portion and projecting substantially perpendicularly relative to the axis of the cylindrical portion. The planar portion 27 includes a first abutment 28, a first planar surface 29 (see figure 8), a second planar surface 30 (see figure 7) and the cylindrical portion includes a slot 31 (see figure 1). Fixed structure 36 is contained within the latch housing 13 (see figure 1A and figure 10) and includes a hole 38 best seen in figure 5 with abutment portions 40 (see figure 1A) and rotation stops 42. A bias means in the form of spring 32 biases the pawl retainer 16 in the direction of arrow A of figure 8. Operation of the latch assembly is as follows:- With reference to figures 1A,2 and 8 the latch assembly is shown in a closed position with an actuating portion of the pawl retainer, in the form of end 26A of the cylindrical portion, being substantially flush with the latch housing 13 and with the pawl 18 in its first retaining position wherein third arm 22 engages the claw to retain the claw in the first latched position. It should be noted that first planar surface 29 rests upon first arm 20 as a result of the spring 32 forcing the pawl retainer in the direction of arrow A of figure 8. In this position the pawl retainer 16 is s-nted from rotating by contact of edges of the planar portion 27 with the hole 38. In particular the general plane PI of the planar portion 27 is out of plane with respect to the general plane P2 of the pawl 18. Operation of the boot release causes second arm 21 to be driven in an anticlockwise direction when viewing figure 1A to position as shown in the figure 3, wherein the first planar surface 29 of the planar portion 27 no longer rests on first arm 20 and is therefore biased by the spring 32 into the position shown most clearly in figure 9. In this position end 26A of the cylindrical portion 26 of the pawl retainer 16 stands proud of the latch housing 13 and the plane of the planar portion 27 is substantially in line with the plane P2 of the pawl 18. When the pawl retainer 16 is in its second retaining position as shown in figures 3, 4 and 9 it is prevented from rotating by guide portions (not shown) and this ensures that the pawl remains in its second released position by the co-operation of first abutment 28 with first arm 20. In this position the pawl is incapable of retaining the claw in its first latched position thus when the boot is slammed shut and a striker 9 moves from the remote position R to the engaged position E and the claw achieves its latched position there is nothing to ensure it remains in its latched position and the boot will spring back open again under the influence of boot opening springs or the like. In order to secure the boot closed two distinct actions need to take place :- a) Firstly the pawl retainer 16 must be moved from its second retaining position as shown in figure 3,4 and 9 to its first released position as shown in figures 1A, 2 and 8. This is achieved by say thumb pressure on end 26A to move it substantially flush with the latch housing. Once in this position the resilient means acting upon the pawl rotates it in a clockwise direction to the position shown in figure 1A. Thumb pressure can then be removed from the end 26A oπ--Uhe first planscsurface 29 will abut first arm 20. b) The boot lid is then subsequently slammed shut wherein the pawl rotates slightly in an anticlockwise direction as the claw passes third arm 22 but not sufficiently such that first arm 20 disengages first planar surface 29. Thus this two stage operation is less likely to be achieved by a child especially when the latch is mounted on the boot lid which when in an open position moves the latch to a relatively high position out of reach of children. Opening of the boot again results in the pawl moving from the position shown in figure 1 A all the way to the position shown in figure 3 and thus allowing the pawl retainer to achieve its position as shown in figures 3,4 and 9 wherein first abutment 28 again retains the pawl 18 in this position thus ensuring that every time the boot is opened a dual action closing sequence is required as described above. In the event that it is unlikely that children are to be trapped in the boot, the dual action closing sequence can be temporarily overridden. Thus by pushing the pawl retainer into the housing such that end 26A is recessed relative to the latch housing 13 and then subsequently rotating the pawl retainer such that first planar surface contacts the abutment portions 40 of the fixed structure 36 (see figures 5,6 and 10) the pawl retainer 16 can be temporarily maintained in this third position, requiring only a slamming of the boot to secure it in its closed position. The slot 31 can be conveniently used in conjunction with a screwdriver or even the automobile keys to move the pawl retainer 16 to and from its third position. It should be noted from figure 10 that the end 26A is recessed relative to the latched housing 13 thus preventing movement of the pawl retainer 16 to its third position inadvertently by thumb pressure. It should further be noted that movement of the pawl retainer between its first released and secon--- retained position is limited to linear movement, rotation being prevented by the hole 38 and also the guides, and movement between the first released position and the third position requires linear and rotational movement. When the boot is open, the latch and in particular the end 26A of the pawl retainer is accessible for operation. However when the boot is closed access to end 26A is neither required nor possible since it is concealed behind the boot door skin or vehicle body. Thus no extra holes are required in the door skin/body and the features that provide for the dual action closing sequence can conveniently be incorporated in to the latch.

Claims: CLAIMS 1. A latch including a latch bolt moveable between a latched position at which it is capable of retaining a striker in an engaged position and an unlatched position at which the striker is free to move between the engaged position and a remote position and a first retaining means moveable between a retaining position at which it retains the latch bolt in its latched position and a released position at which it releases the latch bolt from its latched position and a second retaining means for releasably retaining the first retaining means in its released position following unlatching of the latch, the second retaining means further retaining the first retaining means in its released position following movement of a striker from the remote position to the engaged position. 2. A latch as defined in claim 1 in which the second retaining means includes a first abutment for engagement with a first portion of the first retaining means to retain the first retaining means in its second released position. 3. A latch as defined in claim 2 in which the first abutment is disengaged from the first portion to release the first retaining means from its second released position. 4. A latch as defined in claim 3 in which the first portion moves in a plane as the first retaining means moves between its first and second positions and the first abutment is disengaged by moving it out of the plane. 5. A latch as defined in any preceding claim in which the second retaining means at least moves between a first released position at which it releases the first retaining means from its second released position, and a second retaining position at which it retains the first retaining means in its second released position. 6. A latch as defined in claim 5 in which the second retaining means moves linearly between its first released and second retaining position. 7. A latch as defined in claim 6 in which guides prevent the second retaining means from rotating when positioned at or between its first released and second retaining position. 8. A !f.tch as defined in any one of claims 5 to 7 in which the .-second retaining means is biased towards its second retaining position by bias means. 9. A latch as defined in any one of claims 5 to 8 in which the second retaining means is prevented from moving past the second retaining position by contact with fixed structure of the latch. 10. A latch as defined in any one of claims 5 to 9 in which the second retaining means can be temporarily retained in a third position at which it releases the first retaining means from its second released position. 11. A latch as defined in claim 10 in which the second retaining means at least rotates when moving to or from the third position. 12. A latch as defined in claims 10 or 11 in which the second retaining means is temporarily retained in the third position by contact with fixed structure of the latch. 13. A latch as defined in any one of claims 10 to 12 when dependent upon claim 4 in which the first abutment of the second retaining means is positioned on the same side of the plane when the second retaining means is in its first released and third positions. 14. A latch as defined in any one of claims 5 to 13 in which an actuating portion of the second release means stands proud of adjacent structure or adjacent structure of the latch when the second release means is in its second retaining position. 15. A latch as defined in any one of claims 5 to 14 in which an actuating portion of the second release means is substantially flush with adjacent structure or adjacent structure of the latch when the second release means is in its first released position. 16. A latch as defined in one of claims 10 to 13 or 14 or 15 when dependent upon claim 10 in which an actuating portion of the second release means is recessed into adjacent structure or adjacent structure of the latch when the second release means is in its third nosition. 17. A latch as defined in any preceding claim in which the second retaining means is a pawl retainer. 18. A latch as defined in any preceding claim in which the first retaining means rotates between its first retained and second released positions. 19. A latch as defined in any preceding claim in which the first retaining means is biased towards its first position by biased means. 20. A latch as defined in any preceding claim in which the first retaining means is a pawl. 21. A latch as defined in any preceding claim in which the latch bolt rotates between its first latch and second unlatched position. 22. A latch as defined in any preceding claim in which the latch bolt is biased towards its second unlatched position by bias means. 23. A latch as defined in any preceding claim in which the latch bolt is a claw. 24. A vehicle including a latch as defined in any preceding claim. 25. A vehicle as defined in claim 24 in which the latch secures a boot lid of the vehicle. 26. A vehicle as defined in claim 25 in which the latch is mounted on the boot lid of the vehicle. 27. A vehicle as defined in claim 25 or 26 in which the second retaining means is not accessible when the boot lid is closed. 28. A latch or a vehicle as herein before described with reference to or as shown in the figures.

Inventors: LI MARK HAO, WILLIAMS DAVID, LI, MARK, HAO, WILLIAMS, DAVID
Applicants: LI MARK HAO, MERITOR LIGHT VEHICLE SYS LTD, WILLIAMS DAVID, LI, MARK, HAO, MERITOR LIGHT VEHICLE SYSTEMS (UK) LIMITED, WILLIAMS, DAVID
Application year: 2000
Main classification: E05B65
IPC codes: E05B65