Vehicle door latches

Abstract: In a cable latch system for a vehicle door, the inside door handle (14) is connected by a single push/pull control cable (11) to a bellcrank lever (18) mounted on the latch housing. The bellcrank lever (18) is itself connected to the locking and release levers (15 and 16) of the latch by a vertically disposed spring-loaded push/pull element (21).

Description: This invention relates to door latch systems for motor vehicles and, in particular, to means for interconnecting a latch mechanism on a vehicle door with the inner door handle, and in particular to a vehicle door latch system with the features of the pre-characterizing part of claim 1. In the prior art forming the starting point of the invention (EP - A - 0 169 644) there is described a vehicle door latch system comprising a latch mechanism mounted on a vehicle door and having a release lever operable to release the latch mechanism, and a locking lever having a locked position in which release of the latch mechanism is prevented and an unlocked position in which release of the latch mechanism is enabled. A handle is mounted on the door remote from the latch mechanism and manually operable for releasing, locking, and unlocking the latch mechanism, the handle being connected to the latch mechanism, i. e. to both the locking lever and the release lever, by a single push/pull control cable. In this prior art vehicle door latch system the single push/pull control cable is bent through an angle of approximately 90° from the end connected to the inside door handle to the end connected to the levers in the latch mechanism. In fact the use of the single push/pull control cable instead of straight control rods (as proposed for example in DE - A - 19 35 280 ) has the only reason that otherwise the possibilities to position both parts of the latch system would be severely restricted. The single push/pull control cable is rather flexible and can be arranged within the door interior space to avoid a collision with other structural parts as e. g. the lifting equipment for the glass-panel of the side window. With the small packaging space available within a vehicle side door, under specific circumstances the required bending of the push/pull control cable may be difficult to achieve and high operating loads may accordingly be required to effect latch locking or release in particular if the radius of the necessary bend is quite small. In the prior art from DE - A - 19 35 280 mentioned above there is disclosed a vehicle door latch system comprising a latch mechanism for mounting on a vehicle door with no details of the latch mechanism as such. A handle mounted on the door remote from the latch mechanism is manually operable for releasing the latch mechanism. No further details are given whether this handle is operable for locking and unlocking, too. The handle is connected to the latch mechanism by means of a single push rod which is stiff and has to be disposed in a straight line throughout its length. In order to transfer the straight movement of the push rod into the movement necessary to be effected in the latch mechanism, here a bellcrank lever is mounted on or next to the latch mechanism and as it seems on a latch housing. No variety of positions of the different parts of the latch system can be achieved with this arrangement. Following this explanation of the prior art systems, it is an object of the present invention to provide a vehicle door latch system which on the one hand provides for flexibility in positioning of the parts of the system, on the other hand offers low operating loads for latch locking and release under all circumstances. The object of the present invention is achieved by a vehicle door latch system with the features of the characterizing part of claim 1. The bellcrank lever is preferably mounted on the latch housing and may be disposed either above or below the locking and release levers depending upon the geometry of the latch. The essential inventive idea is to combine a push/pull control cable with a bellcrank lever in line so that the single push/pull control cable can form slight bends with large radii and therefore can avoid any collision with other structural parts of the door interior, and the bellcrank lever at the latch housing forms the structural part specifically suited for a sharp 90° - or even sharper bending. The door latch system of EP - A - 0 169 644 is such that connection of the cable to the locking and release levers cannot practically be effected adjacent the vehicle assembly line. As a result, handle, cable and latch are supplied pre-assembled. This produces a problem in palletising the components being supplied to the assembly line. The present invention, however, gives the possibility that the handle and cable are supplied pre-assembled and the cable is attached to the bellcrank lever on or adjacent the vehicle assembly line. In the drawings Fig. 1 illustrates the door latch system of EP - A - 0 169 644, Fig. 2 illustrates schematically the door latch system of the present invention, Fig. 3 is a somewhat more detailed illustration of the door latch system of fig. 2, Fig. 4 is a vertical sectional view of a door latch in accordance with a further aspect of the invention, and Fig. 5 is a view of the latch of fig. 4 taken at right angles to fig. 4. The known latch system shown in fig. 1 comprises a handle 10, a single push/pull control cable (Bowden cable) 11 and a latch mechanism 12 in a latch housing 9 for mounting on a motor vehicle door in the relative positions shown in fig. 1. The handle 10 comprises a moulded plastics housing 13 and a pivotally mounted handgrip element 14 connected to the inner element of the Bowden cable 11 in such a manner that manual depression of the handgrip element 14 serves to push the inner cable element to effect a locking operation. Rotation of the handgrip element 14 in the opposite direction serves to pull on the inner cable element to release the latch. As shown in fig. 1, that part of the Bowden cable 11 connected to the handle 10 is disposed horizontally whereas that portion of the Bowden cable 11 connected to the latch mechanism 12 is disposed vertically. The bending of the Bowden cable 11 in the manner illustrated in fig. 1 can create packaging problems within the confines of a vehicle door and, if acute bending of the cable is effected, this can seriously affect the "feel" and, in extreme cases, the functioning of the latch. Connection of the inner element of the Bowden cable 11 to the locking lever 15 and release lever 16 is effected in the manner illustrated in fig. 3A of the drawings of EP - A - 0 169 644, to which reference should be made. Fig. 2 shows the latch system of the present invention, like parts being referred to by the same reference numerals used in fig. 1. A bracket 17 is mounted on the latch housing 9 and carries a bellcrank lever 18. The Bowden cable 11 is attached to one arm 19 of the bellcrank lever 18 and the other arm 20 of the bellcrank lever 18 is connected by a spring-loaded push/pull element 21 to the locking and release levers 15 and 16. The manner of operation of the latch assembly is as described in EP - A - 0 169 644. Turning next to fig. 3, this shows the latch system of fig. 2 in more detail and the same reference numerals are again employed to indicate like parts of the system. The handgrip element 14 has a pivotal mounting 22 and can be moved either clockwise or anti-clockwise from the position shown in fig. 3. The handgrip element 14 is formed integrally with an arm 23 to which the inner element of the Bowden cable 11 is attached. Clockwise movement of the handgrip element 14, i. e. movement inwardly of the door panel on which the handle 10 is mounted, serves to push the cable element to the left as viewed in fig. 3. The bellcrank lever 18 is pivotally mounted at pivot mounting 24 on the bracket 17 so that, as the inner cable element is moved to the left as viewed in fig. 3, the bellcrank lever 18 is caused to pivot in an anticlockwise direction about its pivot mounting 24 so that a downward force is applied to the push-pull element 21, here a cable, connected to the locking and release levers 15 and 16. A locking action is thus obtained, just as described in EP - A - 0 169 644. As will be appreciated, however, horizontal movement of the inner element of the Bowden cable 11 is translated into vertical movement of the push-pull element 21 without any significant bending of the cables being involved. This significantly improves the "feel" of the latch, simplifies packaging of the latch system within the available space inside the door panel and avoids excessive loading of the cable. In like manner, when the handgrip element 14 is moved in an anti-clockwise direction, i. e. outwardly of the door panel, the inner element of the Bowden cable 11 is pulled to the right as viewed in fig. 3. This causes the bell-crank lever 18 to be rotated in a clockwise direction to apply an upwardly directed pull to the push-pull element (cable) 21 to release the latch. Connection of the Bowden cable 11 to the latch assembly involves attachment of the inner cable element to the bellcrank lever 18 and the sheath or outer element to a fixture on the bracket 17. Such attachment operations can be effected, if required, at a position on or adjacent the vehicle assembly line. The latch assembly 12 can thus be dispatched to the vehicle assembly line separately from the handle 10 and cable 11. Palletisation of the latch components can thus be simplified as compared to the prior art latch system. A separate latch assembly having the features described above is shown in fig. 4 and 5 and the same reference numerals are again employed to indicate like parts of the latch. It is to be noted, however, that the bell-crank lever 18 of fig. 4 and 5 is disposed beneath the locking and release levers 15 and 16 whereas, in the system of fig. 2 and 3, the bellcrank lever 18 is disposed above the locking and release levers 15 and 16. As shown in fig. 4 and 5, the bellcrank lever 18 is pivotally mounted, by means of a stepped pin (rivet) 25, on the bracket or back plate 17. One arm 20 of the bellcrank lever 18 terminates in a cylindrical socket formation which receives an end fitting of the vertical cable 21 which extends upwardly to the locking and release levers 15 and 16. The other arm 19 of the bellcrank lever 18 terminates in a like cylindrical socket formation to which the inner element of a Bowden cable mechanism, corresponding to the Bowden cable 11 of fig. 2 and 3, can be attached. The outer element of the Bowden cable mechanism is anchored to a jaw formation 26 provided by part of the back plate 17. The bellcrank lever 18 is formed as a plastics moulding from a polyacetal resin and is located between the back plate 17 and a bellcrank holder 27 which protects and supports the bellcrank lever 18. The holder 27 is alos formed as a plastics moulding from a polyacetal resin. It includes a recessed portion within which the head of the stepped pin (rivet) 25 is located such that the end face of the pin (rivet) 25 is flush with the presented face of the holder 27 and presents a clean line. The mode of operation of the latch of fig. 4 and 5, including movement of the locking and release levers 15 and 16 between the positions corresponding to locking, unlocking and release of the latch bolt 28, is as described. Important advantages of the latch shown in fig. 4 and 5 as well are that the latch can be packaged more effectively in a restricted space, the "feel" of the latch is improved as a result of the Bowden cable 11 not being subjected to substantial bending, and the installation of the latch in the vehicle door is facilitated.

Claims: A vehicle door latch system comprising in a latch housing (9) to be mounted on the vehicle door a latch mechanism (12) having a release lever (16) operable to release the latch mechanism (12) and a locking lever (15) having a locked position in which release of the latch mechanism (12) is prevented and an unlocked position in which release of the latch mechanism (12) is enabled, and a handle (10) to be mounted on the vehicle door remote from the latch mechanism (12) and manually operable for releasing, locking and unlocking the latch mechanism (12), the handle (10) being connected by a single push/pull control cable (11) and a spring loaded push/pull element (21) to both the locking lever (15) and release lever (16) of the latch mechanism (12), characterized in that a bellcrank lever (18) is pivotally mounted on the latch housing (9), the push/pull control cable (11) is connected to one arm (19) of the bellcrank lever (18) the levers (15, 16) are connected to the other arm (20) of the bellcrank lever (18) by means of the spring-loaded push/pull element (21), and with the vehicle door latch system mounted on the vehicle door the push/pull control cable (11) is disposed substantially horizontally throughout its length and the spring-loaded push/pull element (21) is vertically disposed on the latch housing (9). A vehicle door latch system according to claim 1, characterized in that the bell-crank lever (18) is pivotally mounted on a bracket (17) attached to the latch housing (9). A vehicle door latch system according to claim 2, characterized in that the bell-crank lever (18) is formed as a plastics moulding and is rotatable relative to a pin (25) which extends between the bracket (17) and a holder (27) or cover for the bellcrank lever (18).

Inventors: ROGERS WILFRID DAVID, ROGERS, WILFRID DAVID
Applicants: BOCKLENBERG & MOTTE BOMORO, BOMORO BOCKLENBERG & MOTTE GMBH & CO. KG
Application year: 1989
Main classification: E05B65
IPC codes: E05B65, E05B53