GB2275727A

GB2275727A - Vehicle door with inertia responsive latch

Info

Publication number: GB2275727A
Application number: GB9304325A
Authority: GB
Inventors: David Edward Hughes; Tony James Fowler
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1993-03-03
Filing date: 1993-03-03
Publication date: 1994-09-07
Also published as: GB9304325D0

Abstract

A vehicle door arrangement has a door 22 such as that of a luggage compartment or a tailgate of a motor vehicle a door frame and a latch 1 comprising a striker bar 6 and a retaining mechanism which includes an inertia activated safety device e.g. a pivotally mounted safety lever 8 having a centre of gravity spaced from its pivotal axis 20. The safety lever is normally in a first position where it does not obstruct release operation of the mechanism and is rotatable about its pivotal axis 20, by the effects of inertia on the lever 8 in the event of vehicle (off-side) impact, to a second position where the lever 8 obstructs the release operation of the mechanism. The safety lever 8 may be provided with a toggle spring 10 which will hold the safety lever 8 in the second position until it is returned to the first position by e.g. a release lever. <IMAGE>

Description

Safety Vehicle Door Arrangement This invention relates to a safety vehicle door arrangement, particularly but not exclusively a luggage compartment door -or tailgate arrangement of a motor vehicle.

The problem of vehicle doors opening in response to rapid acceleration or deceleration forces accompanying vehicle impact has been the subject of many proposals to reduce or prevent such occurrences. Attention has been directed mainly towards personnel doors and reference may be made to the disclosures of the following published patent specifications:- GB 1 161 602, GB 1 203 153, GB 1 219 234, USP 3 719 248, USP 3 799 596 and laid open DE 2 658 153.

While the aforementioned patent specifications disclose inertia-activated safety devices to block or balance the effects of inertia on latch components which would otherwise tend to cause release of the latch, such devices are of such design as to resume their normal position once the adverse acceleration or deceleration forces are removed. This is an important feature for latches for personnel doors since normal manual opening of such doors should be possible after vehicle impact to permit the unhindered escape or removal of personnel.

In the case of luggage compartment doors, tailgates or other vehicle doors which are transversely mounted and particularly when hinged at the top, there is a secondary danger should these be caused to open in response to rapid acceleration or deceleration forces, in that the mass of the door can result in it being torn from its hinges and it flying off to cause another hazard and risk of damage and/or injury. This is particularly the case in the event of motorway accidents when for example a side impact on the vehicle could result in a tailgate being thrown into the path of high speed traffic in the counterflow carriageway.

According to one aspect of the present invention there is provided a vehicle door arrangement comprising a door, a door frame and a latch comprising a striker bar and a retaining mechanism including an inertia activated safety device wherein the vehicle door is a transversely mounted vehicle door and the inertia activated safety device which is normally in a first position where it does not obstruct release operation of the retaining mechanism is movable by the effects of inertia to a second position where it obstructs release operation of the retaining mechanism in the event of vehicle side impact.

According to a second aspect of the present invention there is provided a vehicle door arrangement comprising a door, a door frame and a latch comprising a striker bar and a retaining mechanism including an inertia activated safety device wherein the inertia activated safety device which is normally in a first position where it does not obstruct release operation of the retaining mechanism is movable by the effects of inertia to a second position where it obstructs release operation of the retaining mechanism in the event of vehicle impact and means to retain the safety device in its second position after removal of the effects of inertia tending to move the safety device.

It is preferred that the inertia activated safety device comprises a pivotally mounted safety lever having a centre of gravity spaced from its pivotal axis and rotatable by the effects of inertia on the safety lever from its first position to its second position.

The pivotally mounted inertia activated safety lever preferably comprises a cranked lever and it is preferably loaded at the end nearer to the centre of gravity to enhance the effects of inertia.

The safety lever is preferably mounted to hang from its pivotal axis under the influence of gravity with the preferred orientation of the axis being directed substantially fore and aft of the vehicle.

When employed, the means to retain the safety device in its second position after removal of the effects of inertia tending to move the safety device may be a mechanical or spring clip for example but it is preferably a toggle spring which is caused by movement of the safety device from its first position to its second position, to pass through a condition in which its tension or compression reaches a maximum.

The toggle spring, when employed with the inertia activated safety lever, is preferably connected to the end of the lever, particularly to the end on that side of the pivotal axis remote from the centre of gravity. It preferably comprises a circular tension spring with ends extending in directions parallel to its axis to permit their simple location connection to the lever and directly or indirectly to the vehicle respectively. It will be appreciated that the positions of the respective connections in relation to the pivotal axis of the lever will be such that when the lever is caused to rotate progressively the toggle spring tension is caused to rise to a maximum and thereafter to be reduced. In this manner the spring may be termed as functioning as an over-centre or toggle spring.

When means are provided to retain the safety device in its second position after removal of the effects of inertia tending to move the safety device, it is preferred that an additional means to enable the safety device to be returned at will to its first position is also provided. Such additional means may take the form of a release lever which may be operated manually or by motor to reverse the movement of the safety device, and for example may cause a toggle spring to be taken back through its condition of maximum resistance to rotation of a safety lever, to restore the device to its first position. Such additional means such as a release lever may be incorporated as a component of the retaining mechanism.

In the second aspect of this invention it is preferred that the vehicle door is transversely mounted and the vehicle impact is a vehicle side impact.

The vehicle side impact referred to herein is preferably a vehicle off-side impact.

In a preferred embodiment of this invention the retaining mechanism comprises a releasable pawl which maintains the latch in its closed position, said pawl being optionally fitted with a first spring to resist release of the pawl and opening of the latch as a consequence of the effects of inertia on the pawl as may be caused by vehicle impact and a pivotally mounted inertia activated safety lever having a centre of gravity spaced from its pivotal axis and normally taking up a first position where it does not obstruct release operation of the pawl, so that in the event of said vehicle impact, the effects of inertia on the lever will rotate it about said pivotal axis to a second position where it obstructs release operation of the pawl, the strength of the first spring, when fitted, and the safety lever being loaded and its centre of gravity positioned to ensure that in said event, rotation of the safety lever to the second position will occur before release of the pawl.

It is preferred that the striker bar of the latch is mounted on the door of the vehicle and the retaining mechanism is mounted on the door frame.

While the dimensions of the safety lever preferably employed will be determined very largely by the availability of space, the loading and, when employed, the strengths of first spring and the toggle spring will preferably be adjusted so that the effects of inertia at vehicle impact forces of, for example, at least lOG, preferably at least 20gut will cause the lever to rotate to its second position.

The releasable pawl of the preferred embodiment may be any pivoted lever which will suitably engage directly or indirectly with the striker bar to retain the door in its closed position until vehicle access is required. Manual or motor operation of the pawl against the effect of the first spring can be effected to normally release the pawl from its engaged position. It is preferred that in its engaged position it engages the striker bar indirectly and more preferably via an intermediate latching plate.

The strength of the first spring is preferably such as to resist disengagement of the pawl at vehicle impact forces up to at least lOG, preferably up to at least 30G, for example but not so high as to make normal operation of the pawl difficult. Accordingly, the effort required to directly or indirectly operate the pawl normally is preferably in the region of 12N + 3N.

The latching plate is preferably of the rotary type comprising a rotable plate having a profiled channel cut in its periphery to be engaged by the striker bar so that the plate rotates to bring an edge of the channel into contact with the pawl.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 illustrates the rear view of a motor vehicle fitted with a safety door arrangement according to this invention; Figure 2 illustrates the components of the vehicle latch employed in the region of the vehicle shown in Figure 1 and indicated by the reference numeral 24.

Figure 3 illustrates the safety lever of Figure 2 as viewed in the direction of arrow A in Figure 2.

Figures 2 and 3 which are approximately to a scale of 2:1 of actual sizes have like numbers corresponding.

With reference to Figure 1: 21 indicates generally the rear view of a motor vehicle having a vehicle door comprising a tailgate 22 hinged along its top edge by the hinges 23 attached to the door frame 25. The vehicle door arrangement has a latch as shown in Figures 2 and 3 mounted in the region of the vehicle shown generally by the numeral 24.

Arrow X in Figure 1 indicates the direction of a side impact in response to which the safety lever shown in Figures 2 and 3 operates.

Referring - now to both Figures 2 and 3: in Figure 2 an inertia activated safety lever is shown in phantom line as well as in solid line to indicate its position in its second position and numbered parts are accordingly suffixed 'a; 1 indicates generally the components of a vehicle door latch comprising a releasable pawl 2 pivoted on an axle 3 aligned approximately to the fore and aft directions of the vehicle, and engaging a latching plate 5 (shown in part) at 18 with the latch being in its closed position.This closed position is reached by the latching plate 5, in the form of a plate rotatable about axle 16, being contacted by a striker bar 6 mounted on the door so that a reinforced region 17 of channel 19 cut in its periphery is hit by the bar and rotates the plate clockwise to effectively enclose the striker bar 6 and to a point where the pawl can engage the plate at 18. Movement of the striker bar upwards with the vehicle door (not shown in Figures 2 and 3) to which it is attached is then clearly prevented. However, it can be seen that anti-clockwise movement of the pawl 2 either manually or via a motorised lever (not shown) will release the latching plate 5 and permit the vehicle door to be opened.The pawl 2 is held in contact with the latching plate 5 by the spring 4, attached to the vehicle at the other end (not shown) which also serves to counter-balance the effects of inertia up to a vehicle impact force of for example at least approximately 30G. The effect of the spring 4 on the pawl 2 when the latching plate 5 is not in position may be checked with a stop (not shown) against which the pawl may rest.

7 indicates generally an inertia activated safety lever employed according to this invention positioned in relation to the pawl 2 and which comprises a cranked lever 8 pivoted on an axle 9 aligned approximately in the fore and aft directions of the vehicle and positioned above the centre of gravity of the lever. The lever is loaded at its bottom end by a steel bar 14, having a major diameter of 6 mm, fixed to the lever. The upper end of the lever is provided with a hole through which an end il of a circular tension toggle spring 10 is inserted and thereby connected. The other end 12 of the toggle spring 10 is inserted through a similar hole in a vehicle bracket 15 (as shown in broken away fashion in Figure 3) and thereby connected.

The lever 8 is provided with a tab 13 to assist restoration of the safety lever from the second position to its normal first position. The tab may be operated manually or by contacting it with, and employing, a release lever (not shown) which may be incorporated in the latch construction.

In operation of the safety aspects of the safety vehicle door arrangement of this invention; an impact force of 20G applied in the direction X to the vehicle of Figure 1 fitted with the latch having the safety lever as shown in Figures 2 and 3, causes the effects of inertia to act on the pawl 2 and the safety lever 8 in a manner tending to turn them anti-clockwise about their respective axles 3 and 9. The spring 4 is dimensioned to restrain the tendency for the pawl 2 to rotate. The toggle spring 10, however and the steel bar 14 are dimensioned to permit the lever 8 to rotate whereby the toggle spring 10 passes through a point of maximum tension when the ends 11 and 12 become aligned with the axis 20 of the axle 9 and take up the second position as shown in phantom lines. In its second position, it will be seen that movement of the pawl to release the latch is prevented and this situation will prevail until the lever 8 is returned to its first position. As indicated above, this may be effected manually directly or by lever or by motor.

In the above description with reference to Figures 1 to 3 the striker bar is attached to the vehicle door, in approximate fore and aft alignment with the vehicle, and the remaining components of the latch are attached to the door frame.

It will be appreciated that in an alternative arrangement to that described here, the striker bar may be fitted to the door frame and the other components of the latch fitted to the door.

Claims

1. A vehicle door arrangement comprising a door, a door frame and a latch comprising a striker bar and a retaining mechanism including an inertia activated safety device wherein the vehicle door is a transversely mounted vehicle door and the inertia activated safety device which is normally in a first position where it does not obstruct release operation of the retaining mechanism is moveable by the effects of inertia to a second position where it obstructs release operation of the retaining mechanism in the event of vehicle side impact.

2. A vehicle door arrangement comprising a door, a door frame and a latch, the latch comprising a striker bar and a retaining mechanism including an inertia activated safety device wherein the inertia activated safety device which is normally in a first position where it does not obstruct release operation of the retaining mechanism is moveable by the effects of inertia to a second position where it obstructs release operation of the retaining mechanism in the event of vehicle impact and means to retain the safety device in its second position after removal of the effects of inertia tending to move the safety device.

3. A vehicle door arrangement as claimed in either Claim 1 or Claim 2 wherein the inertia activated safety device comprises a pivotally mounted safety lever having a centre of gravity spaced from its pivotal axis and rotatable by the effects of inertia on the safety lever from its first position to its second position.

4. A vehicle door arrangement as claimed in Claim 3 wherein the retaining mechanism comprises a releasable pawl which maintains the latch in its closed position, said pawl being optionally fitted with a first spring to resist release of the pawl and opening of the latch as a consequence of the effects of inertia on the pawl as may be caused by vehicle impact and a pivotally mounted inertia activated safety lever having a centre of gravity spaced from its pivotal axis and normally taking up a first position where it does not obstruct release operation of the pawl so that in the event of said vehicle impact the effects of inertia on the lever will rotate it about said pivotal axis to a second position where it obstructs release operation of the pawl, the strength of the first spring, when fitted, and the safety lever being loaded and its centre of gravity positioned to ensure that in said event, rotation of the safety lever to the second position will occur before release of the pawl.

5. A vehicle door arrangement as claimed in either Claim 3 or Claim 4 wherein the safety lever comprises a cranked lever.

6. A vehicle door arrangement as claimed in any one of Claims 3 to 5 wherein the safety lever is mounted to hang from its pivotal axis with orientation of the axis being directed substantially fore and aft of the vehicle.

7. A vehicle door arrangement as claimed in any one of Claims 2 to 6 wherein the means to retain the safety device in its second position after removal of the effects of inertia tending to move the safety device is a toggle spring which is caused by movement of the safety device from its first position to its second position to pass through a condition in which its tension or compression reaches a maximum.

8. A vehicle door arrangement as claimed in Claim 7 wherein the toggle spring is a circular tension spring with ends extending in directions parallel with its axis.

9. A vehicle door arrangement as claimed in any one of Claims 2 to 8 wherein an additional means is provided to enable the safety device to be returned at will from its second position to its first position.

10. A vehicle door arrangement as claimed in any one of Claims 2 to 9 which is a transversely mounted vehicle door.

11. A vehicle door arrangement as claimed in any one of the preceding claims wherein the striker bar is mounted on the door and the retaining mechanism is mounted on the door frame.

12. A vehicle door arrangement as claimed in any one of Claims 4 to 11 wherein release of the pawl is resisted at an impact force of up to at least lOG, preferably up to at least 30G.

13. A vehicle door arrangement as claimed in any one of the preceding claims wherein the impact force required to activate the inertia activated safety device is at least lOG, preferably at least 20G.

14. A vehicle door arrangement as claimed in any one of the preceding claims wherein the effort required to directly or indirectly release the retaining mechanism normally is in the region of 12N + 3N.

15. A vehicle door arrangement substantially as herein described with reference to the accompanying drawings.