Latch assemblies for vehicle bonnets

Abstract: A latch assembly for a vehicle bonnet has a funnel portion (3a) for guiding a striker pin into position and a tubular portion (3b) for limiting the misalignment of the striker pin and latch (8) formed as a single integral member (3). The latch (8) is pivotally mounted adjacent one of its ehds and partly projects through a slot (10) in the tubular portion (3b) to engage the head of the striker pin, and is held releasably in engagement by the spring (9). The latch assembly may have two plates (1, 4) through which the integral member (3) passes. Lugs on the integral member (3) are then clamped between the plates (1, 4) to secure it in place. Abutments (A) may be provided to retain the latch (8) in place should its pivot fail. A safety hook may be incorporated, a hook retainer being provided which mounts below and projects through the panel on which it is mounted.

Description: This invention relates to latch assemblies for vehicle bonnets. The term bonnet is used herein to refer to the front luggage boot cover on rear and mid engine vehicles as well as the engine cover on any vehicle, or any similar cover that may be found on a vehicle body. The bonnet covering the front or engine compartment of a vehicle is usually hinged at its rear edge to the scuttle or other part of the vehicle body and is normally held down at its front end by a spring-loaded latch assembly releasable by remote control from inside the vehicle or by an external release device. The latch assembly most commonly used comprises a headed striker pin mounted on the bonnet and adapted, as the bonnet is closed, to pass through an opening in a catch plate secured to the grille surround or other part of the front end of the body, and to then be engaged by a pivotal or slidable catch lever. Such a latch assembly is disclosed by DE-A-1 934 870. Usually there is also a manually releasable safety hook which is pivotally mounted on the body or bonnet and engages with a part of the bonnet or body respectively to prevent the bonnet from opening accidentally if the striker pin has not been fully engaged by the catch lever. The present invention is concerned with solving or at least ameliorating some problems which can arise with existing latch assemblies. In order to provide a positive latching action the head of the striker pin usually has a conical leading portion backed by a latching face which is engaged by the catch lever in the locked condition and extends in a plane normal to the axis of the striker pin. A sharp corner is defined between the latching face and outer face of the conical portion of the head of the pin, and the presence of this sharp corner can, in some circumstances, with existing designs, cause the pin to jam on any protrusion which is present in the region of the catch plate assembly which carries the latch, thereby preventing opening of the bonnet. With existing designs a funnel shaped guide is usually provided on the upper face of the catch plate assembly to cooperate with the conical portion of the head of the striker pin and guide the head of the striker pin towards the position in which it is engaged by the catch lever. The funnel-shaped guide is either an independent member which is secured to the catch plate assembly or it is pressed from the plate assembly. In either case an edge may be defined around the underside of the guide which, due to misalignment of the various parts, in some circumstances may result in the possibility of the latching face corner engaging with that edge to prevent release of the bonnet. According to the invention there is provided a latch assembly for a vehicle bonnet for receiving and releasably retaining a striker pin comprising a latching member for engaging and retaining the striker pin, and a funnel portion for guiding the striker pin into engagement with the latching member, the assembly further comprising a tubular portion into which the head of the striker pin is received and retained and into which the latching member projects for engagement with the striker pin, the tubular portion and the guide funnel being formed as an integral guide funnel and tubular member; characterised in that the assembly has first and second plates secured together through which the integral guide funnel and tubular member passes, the integral funnel and the tubular member having one or more projections which are clamped between the plates, to retain the integral guide funnel and tubular member in position. By using an integral guide funnel and tube member the latch assembly can be arranged such that there are no protruding edges at the junction between the funnel and the tube which might prevent withdrawal of the striker pin, even when the striker pin is being urged sideways due to its initial misalignment. Preferably the guide funnel and the tube member is moulded from a suitable plastics material, such as a polyamide, since it is possible with a moulding to provide a one-piece unit with a consistently smooth internal surface of low friction. As is usual the funnel part can be made wide enough to co-operate with a frusto-conical guide cup which is preferably mounted co-axially behind the head of the striker pin and is spring-loaded to assist in the initial lift of the bonnet when the catch lever is released. The integral guide funnel and tubular member may be secured to the mounting plate assembly by any convenient means. It can be arranged to have a snap connection or a bayonet connection with a plate of the mounting assembly. Rotation of the integral guide funnel and tubular member may be prevented by radial projections. Preferably the tubular portion of the integral guide funnel and tubular member is formed externally with a recess of at least part-annular shape, and the tubular portion is trapped in use between the opposed edges of two plates of the plate assembly, at least one of which projects into the recess, the two plates being secured together. Depending on the application, the integral guide funnel and tubular member may extend upwards so far as to need support, and in this case an extra top plate is fitted. The provision of such a top plate lends itself to a possible arrangement for adjustment of the whole assembly as the top and catch plate assembly together form a sandwich above and below the body panel in which the assembly is mounted. The aperture in the tubular portion through which the catch lever projects is preferably a slot, and it is preferred that the head of the striker pin is of substantially cylindrical shape immediately below the latching face and above the conical portion, and that the depth of this cylindrical portion of the head is made greater than the depth of the slot, to ensure that the corner of the striking face cannot become engaged with the upper edge defining the slot. The length of the tubular portion of the integral guide funnel and tubular member is chosen such that in the event of overslamming of the bonnet, the head of the striker pin cannot protrude sufficiently far below the lower end of the tubular portion such that the latching face might engage with the tube end face. The amount by which the head of the striker pin may extend downwards into the tubular portion is preferably controlled by providing the guide funnel with an upwardly directed boss which is arranged to engage with the mounting for the striker pin head on the overslam. Alternatively boxing of the spring which biasses the guide cup may be used to determine the overslam position of the striker pin head. A preferred embodiment of the invention is concerned with the problem that the pivot pin for the catch lever may, on rare occasions, break. It is desirable to ensure that in the event of a failure of the catch lever pivot the catch lever cannot become disengaged from the head of the striker pin. Therefore in this preferred embodiment of the invention the latch assembly for a vehicle bonnet incorporates a pivoted catch lever for retaining the striker pin in a fastened position, in the closed position of the bonnet, abutment mean are provided adjacent to the catch lever which prevent the catch lever from becoming disengaged from the catch lever head of the striker pin in the event of failure of the pivot for the catch lever. The abutments are provided on the catch plate assembly for the catch lever and one of the abutments is preferably provided by the tubular portion of the integral guide funnel and tube member. Another preferred embodiment of the invention is concerned with the aim that the catch plate assembly should be sufficiently strong to take the maximum force that may be applied to it by the safety hook in the event that the catch lever is released whilst the car is travelling at high speed. In this embodiment of the invention the latch assembly has an associated safety hook assembly comprising a safety hook which is adapted to be pivotally mounted on the vehicle bonnet or vehicle body for engagement with a hook retainer carried by a mounting plate which is adapted to extend (in use) behind the panel of a vehicle body or bonnet respectively, the hook retainer being carried by a portion of the mounting plate which extends through an aperture in the panel. Since the mounting plate extends behind the panel the fixings between the mounting plate and the panel are not subjected to the full load exerted by the hook. The hook retainer is preferably formed as a double thickness of sheet material, one thickness being carried, as just specified, by an integral mounting plate which extends behind the panel, but the other thickness being carried by a separate top plate which is mounted on the outside of the panel, the panel thus being sandwiched between the flanges of the two mounting plates, through which suitable fasteners extend in use. This top plate can be the one mentioned earlier in connection with the additional top support for the funnel and guide tube member. Embodiments of the present invention will now be described in detail, by way of example, with reference to the accompanying drawings in which:- Figures 1, 2 and 3 are respectively a partially sectioned front elevation, plan view and transverse cross-section of a catch plate assembly embodying the first aspect of the invention; Figure 4 is a view similar to Figure 1, showing a modification; Figures 5, 6 and 7 are respectively a front elevation, side view (looking from the right in Fig 5) and inverted plan view of a striker pin assembly in a second embodiment, incorporating also a safety hook, and Figures 8, 9 and 10 are respectively a plan view, front elevation, and transverse section(looking from the left in Fig 9) of a catch plate assembly co-operating with the striker pin assembly of Figures 5, 6 and 7 and incorporating the safety hook. Referring first to Figures 1, 2 and 3, a catch plate assembly comprises a main pressing 1 designed to be secured under a panel or platform 2 on the vehicle bodywork and to receive a central moulded plastics integral funnel and guide tube member 3 which comprises a frusto-conical funnel port on 3a, the smaller-diameter end of which joins a tubular portion 3b. This member 3 is preferably moulded in polyamide material which offers very low friction to the entry of the striker pin (which will be like that of Figures 4, 5 and 6). The funnel and guide tube member 3 is located between the pressing 1 and a second plate 4 and is provided with lugs 5 to hold it in place; it is assembled by inserting it in a enlarged clearance portion 6 of the hole designed to receive it, then moving it laterally to the left (as shown in Figure 1), whereupon the lugs are trapped between the two plates and retain and so prevent rotation of the member 3. A rivet 7 which passes through the main pressing 1 and the second plate 4 forms a pivot pin for a catch lever 8. The catch lever 8 is urged to the engaged position by a spring 9. In the engaged position, an edge of the lever 8 projects into the tubular portion 3b of the integral funnel and guide-tube member 3. A slot 10 in the member 3 provides clearance for the lever to enter the guide tube 3b. The release mechanism, usually a rod or Bowden cable linkage connected through a hole 11 on the free end of the lever 8, is not shown. The lever 8 protrudes through a slot in the front flange of the pressing 1 and this, combined with an abutment or a stop lug A, which is provided adjacent to the pivot pin 7, ensures that, even if the pivot pin were to break in use, the catch lever 8 would not release the headed striker pin. The funnel and guide member 3 extends downwards far enough so that even at the extreme limits on the tolerances of the parts 'overslam' cannot cause the head of the striker pin to pass beyond the lower end of the guide-tube portion 3b with the consequent risk that it could jam there. Figure 4 is a view similar to Figure 1, but showing a modification in that the funnel part 3a of the member 3 extends a substantial distance upwards from the main pressing 1. In this case the main pressing 1 has an additional pressing 12 forming a top plate secured to it. The additional top plate 12 has a through-hole through which the funnel portion 3a passes in order to give additional lateral support to the top end of the funnel portion 3a. Referring now to Figures 5, 6 and 7 these show a striker pin 13 suitable for use with the catch plate assembly of the invention. The striker pin 13 is screwed into a mounting plate 16 which is fixed to the bonnet of the vehicle (not shown). The head of the pin is conical to guide it into the funnel 3a, and is backed by the usual guide cup 14 and spring 15, the latter serving to give the bonnet an initial lift on release of the catch lever 8. In addition, mounted on the same mounting plate 16 is a safety hook 17, urged to its engaged position by a spring 18 and which may be manually released by an integral finger tab 19. The catch plate assembly that co-operates with the striker pin 13 and safety catch shown in Figures 5 to 7 is shown in Figures 8, 9 and 10. A main catch plate pressing 20 carries a combined funnel and guide tube member 3 like that of the embodiment described earlier with reference to Figures 1 to 3, with its associated catch lever 8 on a pivot 7, and a spring 9. In the same plate 20, to the left (as shown in Figure 8) of the member 3, is an opening 21 having a raised lip 22 formed integrally at one edge of the opening (see Fig 10) for engagement by the safety hook 17. The edge of the catch lever 8 that engages the similar pin is chamfered in order that it is more easily pushed aside as the striker pin 13 is introduced into the tubular portion 3b. In addition there is a second pressing 23 forming a top plate, similar to the second plate 4 described above with reference to Figure 4, helping to locate the upper part of the funnel portion 3a of the member 3. This top plate 23 also has a raised portion 24 forming a shroud that reinforces the lip 22, as shown in Figure 10. Thus even if the main bonnet catch is inadvertently released by the driver when the vehicle is travelling at a high speed the sudden upward impact of the safety hook against the lip 22 will not lead to disaster. The top plate 23 has a further use. Whereas the main catch plate 20 is mounted below the body panel or platform 2, the top plate 23 is above it, and so when the catch is assembled the panel 2 is sandwiched between the two said plates 20, 23. This makes lateral adjustment of the catch assembly on mounting particularly easy, with the securing crews passing through elongated or clearance holes in the body panel 2.

Claims: A latch assembly for a vehicle bonnet for receiving and releasably retaining a striker pin (13) comprising a latching member (8) for engaging and retaining the striker pin (13), and a funnel portion (3a) for guiding the striker pin (13) into engagement with the latching member (8), the assembly further comprising a tubular portion (3b) into which the head of the striker pin (13) is received and retained and into which the latching member (8) projects for engagement with the striker pin, the tubular portion (3b) and the guide funnel (3a) being formed as an integral guide funnel and tubular member (3); characterised in that: the assembly has first and second plates (1, 4) secured together through which the integral guide funnel and tubular member (3) passes, the integral guide funnel and tubular member having one or more projections (5) which are clamped between the plates (1, 4), to retain the integral guide funnel and tubular member (3) in position. A latch assembly according to claim 1 in which the integral guide funnel and tubular member (3) is a plastics moulding. A latch assembly according to any preceding claim having a top plate (12) the upper part of the integral guide funnel and tubular member (3) passing through and being supported by the top plate (12). A latch assembly according to any preceding claim in which the latching member (8) is an elongate bar mounted by a pivot (7) on the first and/or second plate (1, 4) and the integral guide funnel and tubular member (3) has a slot (10) in the tubular portion (3b) thereof through which the latching member (8) passes in order to engage the striker pin(13). A latch assembly according to claim 4 having resilient biassing means (9) to urge the latching member (8) towards the tubular portion (3b). A latch assembly according to any one of claims 4 to 5 further comprising abutment means (A) adjacent the pivot (7) of the latching member (8) to restrict movement of the latching member (8) away from the tubular portion (3b) if the pivot (7) should fail. A latch assembly according to any preceding claim further comprising a safety hook (17) adapted for pivotal connection to either one of the bonnet or the vehicle body and a hook retainer adapted for connection to the other one of the bonnet or vehicle body, the hook retainer (22) being carried by a mounting plate (20) adapted to extend behind a panel (2) of the vehicle body or bonnet, the hook retainer (22) being carried on a portion of the mounting plate (20) which extends through an aperture in the panel (2) towards the hook (17). A latch assembly according to claim 7 having an upper plate (23) adapted to be fastened in use to the mounting plate (20), part of the panel (2) being sandwiched therebetween. A latch assembly according to claim 8 in which the upper plate (23) and the first plate (1) are formed as an integral component. A latch assembly according to claim 8 or claim 9 in which the mounting plate (20) and the second plate (4) are formed as an integral component.

Inventors: MORRIS BARRY STANLEY, MORRIS, BARRY STANLEY
Applicants: BLOXWICH ENG, BLOXWICH ENGINEERING LIMITED
Application year: 1990
Main classification: E05B65
IPC codes: E05B65