GB2286624A - Vehicle seat latch and belt reel arrangement - Google Patents

Abstract

A vehicle seat latch arrangement comprises latch means (1) to releasably secure a foldable component of the seat in its correct riding position to the vehicle body 3 wherein the latch (1) is provided with a sensor (7) to sense the secure latching of the seat component in its correct riding position and on so sensing to activate a release mechanism (14), to release a seat belt retractor locking device (16) from a reversible locking position to an unlocking position to permit a seat belt web retained by the reel to be payed out by the reel and the seat belt to be used, only when the seat is properly latched. <IMAGE>

Description

A Vehicle Seat Latch Arrangement This invention relates to a seat latch arrangement for a vehicle seat having a foldable component to which is secured a seat belt. The invention relates particularly, but not exclusively, to a seat latch arrangement for the backrest of a motor vehicle seat, especially a rear seat adapted to accommodate a centre seat passenger, which backrest may be folded downwards.

The fitting of seat belts in motor vehicles is the subject of statutory requirements which extend to the rear seats of private motor vehicles.

With the cost of motoring and of the carriage of goods having increased dramatically in recent years, the popularity of motor vehicles which can easily be adapted from passenger-carrying to goods-carrying, has also increased. This increase has applied particularly to motor vehicles such as so-called hatchbacks and estate cars having rear bench-type seats which may accommodate a centre seat passenger.

While a seat belt for a window seat passenger of a bench seat may take advantage of a window pillar, for example, for one anchorage point for the belt, this is not convenient for a seat belt for a centre seat passenger.

Accordingly, for such a seat belt, it has been proposed to make an anchorage point on the seat itself. When this anchorage point is positioned on a foldable component of the seat, there is a clear danger in that, at least in some cases, the seat belt could be used without the seat component being properly secured in its riding position and thereby the seat belt may be rendered, very largely, ineffective in preventing serious injury in the event of a vehicle collision, for example.

Various devices have been proposed for securing a foldable seat component in its riding position and for providing a warning of such a component not being so properly positioned. In this connection, reference may be made, for example, to the following published patent specifications: DE 2 926 800. DE 2 927 159, DE 2 950 314, GB 2 018 575, GB 2 215 586 and GB 2 249 339. However, most of the proposals made in these specifications do not provide means to prevent the seat belt from being used if the foldable seat component is not in its proper riding position. Further, while the proposals of DE 2 927 159 and of GB 2 249 339 do provide means whereby a seat belt retractor reel is automatically releasably locked if a foldable seat backrest, with which it is associated, is not in a predetermined position, no measures are proposed whereby the secure latching of the backrest in its proper riding position is monitored and the release of the seat belt retractor reel, and thereby use of the seat belt, prevented before such secure latching is established.

According to the present invention there is provided a vehicle seat latch arrangement comprising a latch means to releasably secure a foldable component of the seat in its correct riding position to the vehicle body wherein the latch means is provided with a sensor to sense the secure latching of the seat component in its correct riding position and on so sensing the secure latching of the seat component to activate a release mechanism to release a seat belt retractor reel locking device from a reversible locking position to an unlocking position to permit a seat belt web retained by the reel to be payed out by the reel and the seat belt to be used.

The foldable seat component may be a vehicle seat squab hinged along its bottom front edge for example and to which a backrest may be fixed, but preferably, the foldable seat component is the backrest of a vehicle seat and more especially the backrest of a rear bench seat for accommodating a centre seat passenger. Such a backrest may be hinged along its bottom rear edge, for example.

The latch means is preferably of the rotary type including a pivotally mounted rotor adapted to cooperate with a striker pin. Preferably, the striker pin is fixed to the seat component and the rotor is attached to the vehicle body but alternatively the pin and rotor may be interchanged.

The rotor is preferably a shaped plate having cam surfaces on its periphery and having its pivotal axis parallel to the plate thickness direction. The cam surfaces include a first captive portion shaped to accept the pin on movement of the pin and rotor towards one another in moving the seat component towards its riding position, the first captive portion being so shaped that continued relative movement of the pin and rotor causes the rotor to turn about its pivotal axis to a latching position.

Such relative movement of the pin and the rotor is preferably in a direction transverse to the major axis of the pin and to the pivotal axis of the rotor. It is preferred that the rotor is sprung biassed towards its pin accepting position whereby its movement towards its latching position is against such spring bias.

The sensor with which the latch means is provided is preferably a sprung loaded pawl biassed towards a position in which it can sense that the latch means is securely latching the seat component in its correct riding position.

In the preferred arrangement in which the latch means is of the rotary type, the cam surfaces of the rotor include a second captive portion so positioned on the rotor that when the rotor is in its secure latching position, the pawl locates with the second captive portion. The shape of the pawl and the shape of the second captive portion may be such that in cooperation the pawl releasably secures the rotor in its latching position. The pawl may reach its securing position by riding along the cam surfaces of the rotor or it may be held by a blocking device until the rotor is in the secure latching position when the blocking device is caused to release the pawl into its securing position by movement of the blocking device by relative movement of the pin and the rotor and contact between the pin and the blocking device.

It is preferred that the sensor incorporates a manually operable lever by means of which the sensor may be moved from the position in which it senses the secure latching of the seat component. Accordingly, if the sensor comprises a sprung loaded pawl, a lever is preferably connected to the pawl so that the pawl may be moved against the action of the spring. It is preferred that movement of the sensor by the lever from the position in which it senses the secure latching of the seat component, releases the seat component from its secure latching. A lever connected to a pawl sensor may be rigidly connected or connected through a lost motion link. In the latter case, the lever is preferably connected to a secondary sprung loaded pawl for cooperation with a third captive portion of the cam surfaces of the rotor of a rotor type latch means for releasably securing the latching of the seat component which may be additional to any securing of the latching by the pawl sensor. Such a secondary sprung loaded pawl is preferably connected to the lever such that it is movable through a lost motion link whereby movement of the lever in a direction to move the sensor from a position in which it senses the secure latching of the seat component moves the sensor before it moves the secondary pawl to a position to release the latching of the seat component. It is preferred that any manually operated lever connected to the sensor has associated with it a visual indicator to indicate its position. Such a visual indicator may comprise red and green stripes which may be obscured alternately according to whether the lever is in the position corresponding to secure latching of the seat component or in a position corresponding to the release of such latching.

The sensor should be adapted to activate a release mechanism to release a seat belt retractor reel locking device from a reversible locking position to an unlocking position. Accordingly, the sensor may have associated with it a microswitch or photo-cell for example, by means of which it can, through electrical circuitry, activate an electromagnetically operated lever for example, to release the reel locking device. However, it is preferred that the sensor activates the release mechanism solely through mechanical linkage.

Accordingly, it is preferred that the sensor has connected to it a Bowden-type cable, the other end of which is connected to the retractor reel locking device, so that movement of the sensor in sensing the secure latching of the seat component causes the cable to move to release the locking device. It is preferred that in such an arrangement the cable is sprung-biassed towards movement of the locking device away from its locking position whereby, on the sensor sensing the secure latching of the seat component, the sensor causes the cable to move in the direction of the bias.

The retractor reel locking device is preferably a lever which can be moved into and out of engagement with teeth on the periphery of the reel of the seat belt retractor, corresponding to a locking position and an unlocking position respectively.

It is preferred that the seat belt retractor reel is attached to the foldable seat component. It is preferred also that the foldable seat component is the backrest of a bench seat accommodating a centre seat passenger.

It will be appreciated that for added security more than one vehicle seat latch arrangement may be employed on any one foldable seat component. In the case of a foldable backrest, two latch arrangements are preferred, particularly one at either end of the backrest.

The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a sketch of one latch arrangement according to the present invention showing various positions of the latch components and showing also, connected thereto, a release mechanism for a seat belt retractor reel locking device.

Figure 2 is a sketch showing an alternative latch arrangement to that shown in Figure 1 Figure 3 is a sketch of another alternative latch arrangement to that shown in Figure 1.

With reference to Figure 1; 1 indicates, generally, latch means comprising the shaped plate rotor 2 pivotally mounted on the bodywork 3 of a motor vehicle for movement about the axis 4 extending into the plane of Figure 1.

The rotor 2 is sprung-biassed by spring 5 towards a striker pin accepting position represented by the dotted outline 2'. The striker pin 6 is attached to a folding backrest (not shown) of a rear bench seat of the vehicle.

The position of the pin 6 when the backrest is in an unlatched position is represented by 6'. The latch means 1 also comprises the sensor pawl 7 which is pivotally mounted on the bodywork 3 for movement about axis 8. The spring 9 biasses the sensor pawl 7 towards its secure latching sensing position in which the nose 10 of the sensor pawl 7 locates, in securing manner, with the captive portion 11 of the cam surfaces on the periphery of the rotor 2. The cam surfaces of the rotor 2 have also the captive portion 18 with which the striker pin 6 locates when the rotor is in the secure latching position.

The sensor pawl 7 has attached to it the lever 12 which may be moved to the position, indicated by 12', to release the nose 10 from the captive portion 11 and thereby to release the latch from its secure latching of the backrest. Connected to the sensor pawl 7 at the point indicated by 13 is the inner wire the Bowden cable 14 the outer casing of which is secured at one end to the body work 3 and at its other end to the housing 15 of a seat belt retractor reel mounted on the rear surface of the backrest of the vehicle seat (not shown). The end of the inner wire of the Bowden cable 14 remote from the sensor pawl is connected to the seat belt retractor reel locking device comprising the lever 16 sprung biassed by the spring 17 away from its locking position indicated by 16'.

In its locking position, the lever 16' locks with teeth on the periphery of the seat belt reel (not shown) to prevent its rotation and thereby use of the seat belt.

Operation of the latch arrangement of Figure 1 will now be described. With the backrest in a partly folded down position so that the striker pin 6 is at the position 6', and the lever 12 moved in the direction of the arrow B and the rotor 2 moved under spring action to the position 2', the position of the sensor pawl 7 causes the inner wire of the Bowden cable 14 to be pulled whereby the locking lever 16 takes up the position 16' to lock the seat belt retractor reel. Movement of the backrest and thereby the striker pin in the direction of the arrow A, causes the pin 6 to strike a portion 19 of the cam surfaces of the rotor 2 and rotate the rotor anti-clockwise. During progressive movement of the pin 6 and the rotation of the rotor 2 the cam surfaces of the rotor 2 slide over the pin 6 until the pin 6 locates with the captive portion 18.

Also during the progressive movement of the rotor 2, the nose 10 of the sensor pawl 7 contacts the cam surfaces of the rotor 2 which slide over the nose 10 until the latter locates with the captive portion 11 the position of which corresponds to the rotor having been rotated whereby the pin 6 is located with the captive portion 18. With the nose 10 located with the captive portion 11, the rotor is locked against clockwise rotation and of course against releasing the backrest. The backrest is therefore securely latched to the vehicle bodywork. The location of the nose 10 with the captive portion 11 accordingly senses the secure latching of the backrest and in so doing activates the release of the locking lever 16 by allowing the inner wire of the Bowden cable 14 to move in a direction consistent with extension of the spring 17, thereby permitting the seat belt web retained by the seat belt reel to be payed out and used.

In order to release the backrest, the lever 12 is moved in the direction of arrow B whereby the nose 10 of the sensor pawl 7 is withdrawn from its location with the captive portion 11. The rotor 2 is thus permitted to rotate clockwise to release the striker pin 6 and allow the backrest to be folded down. Withdrawal of the nose 10 of the sensor pawl 7 from its location with the captive portion 11 also causes the inner wire of the Bowden cable 14 to be pulled, thereby moving the locking lever 16 to the position indicated by 16' to lock the seat belt reel against paying out the seat belt web.

With reference to Figure 2; 21 indicates, generally, latch means comprising the shaped plate rotor 22 pivotally mounted on the body work 23 of a motor vehicle for movement about the axis 24 extending into the plane of Figure 2. The rotor 22 is sprung-biassed by spring 25 towards a striker pin accepting position 22'. The striker pin 26 is attached to a folding backrest of a seat of the vehicle. The position of the pin 26 when the backrest is in an unlatched position is represented by 26'. The latch means 21 also comprises the sensor pawl 27 which is pivotally mounted on the body work 23 for movement about the axis 28 extending into the plane of Figure 2. The spring 29 biasses the sensor pawl 27 towards its secure latching position in which the nose 30 of the sensor pawl 27 locates with the captive portion 31 of the cam surfaces on the periphery of the rotor 22. The cam surfaces of the rotor 33 also have the captive portion 38 with which the striker pin 26 locates when the rotor is in the secure latching position. The sensor pawl 27 has attached to it the lever 32 which may be moved to the position indicated by 32' to release the nose 30 from the captive portion 31 and thereby to release the latch from its secure latching of the backrest. Similar to the arrangement shown in Figure 1, the sensor pawl 27 has connected to it a Bowden cable 34 by means of which movement of the sensor pawl 27 can activate a seat belt retractor reel locking device as shown in Figure 1. The latch arrangement of Figure 2 includes a sensor pawl blocking lever 40 pivotally mounted on the bodywork 23 of the vehicle and biassed by the spring 42 towards its blocking position indicated by 40'.

Operation of the latch arrangement of Figure 2 is as follows. With the backrest (not shown) in a partly folded down position so that the striker pin 26 is at the position 26', and the lever 32 moved in the direction of the arrow B and the rotor 22 moved under spring action to the position 22', the sensor pawl 27 takes up the position indicated by 27' and the blocking lever 40 locates under the sensor pawl 27 to restrain it against the action of the spring 29. The rotor 22 is moved under the action of the spring 25 to the position 22'. The position of the sensor pawl 27 causes the inner wire of the Bowden cable 34 to be pulled to lock the seat belt retractor reel.

Movement of the backrest and thereby the striker pin 26 in the direction of the arrow A, causes the pin 26 to strike a portion 39 of the cam surfaces of the rotor 22 and rotate the rotor clockwise. During progressive movement of the pin 26 from the position 26', through the position 26'', and the rotation of the rotor 22, the cam surfaces of the rotor 22 slide over the pin 26 until the pin 26 locates with the captive portion 38. Also during progressive movement of the pin 26, the pin contacts the blocking lever 40, in the position 40', and displaces it against the action of the spring 42 to thereby effect the timely release of the sensor pawl 27 whereby its nose 30 can locate with the captive portion 31 to secure the rotor 22 and thereby the backrest in its secure latching position. The release of the sensor pawl 27 causes the inner wire of the Bowden cable 34 to move in a direction consistent with the unlocking of the seat belt retractor reel o thereby permit the seat belt web retained by the reel to be payed out and used.

The release of the backrest from its secure latching position is effected by movement of the lever 32 in the direction indicated by the arrow B. This movement causes the nose 30 of the sensor pawl 27 to withdraw from location with the captive portion 31 thereby releasing the rotor 22 and allowing its anti-clockwise rotation with release of the striker pin 26. On movement of the striker pin 26 counter to the direction of arrow A, the release of pressure on the blocking lever 40 allows the latter to move to the position 40' to lock the sensor pawl 27 in its withdrawn position. The withdrawal of the nose 30 of the sensor pawl 27 correspondingly causes the inner wire of the cable 34 to be pulled to thereby move the seat belt retractor reel locking device to its locking position to prevent the paying out of the seat belt web and thereby the use of the seat belt.

With reference to Figure 3; 51 indicates, generally, latch means comprising the shaped plate rotor 52 pivotally mounted on the bodywork 53 of a motor vehicle for movement about the axis 54 extending into the plane of Figure 3.

The rotor 52 is sprung-biassed by spring 55 towards a striker pin accepting position indicated by 52'. The striker pin 56 is attached to a folding backrest ( not shown ) of a motor vehicle seat. The position of the pin 56 when the backrest is in an unlatched position is represented by 56'. The latch means 51 also comprises the sensor pawl 57 which is pivotally mounted on the bodywork 53 for movement about axis 88. The spring 59 biasses the sensor pawl 57 towards its secure latching sensing position in which the nose 60 locates with the captive portion 61 of the cam surfaces on the periphery of the rotor 52. The cam surfaces of the rotor have also the captive portion 58 with which the striker pin 56 locates when the rotor is in the secure latching position. In addition, the cam surfaces of the rotor have captive portion 71 with which the nose 70 of the secondary pawl 72 locates when the latch means is in its secure latching position. Connected to the sensor pawl 57 through the lost motion link 74 is the release lever 62 pivotally mounted on the bodywork 53 for movement about axis 73 extending into the plane of Figure 3 to the position 62' through the position 62''. The lever 62 has connected to it the secondary pawl 72 in a manner permitting relative concentric movement, for which purpose a lost motion link 75 is provided. The spring 76 biasses the pawl 72 towards the position in which the nose 70 of the pawl locates with the captive portion 71. Connected to the sensor pawl 57 is the inner wire of the Bowden cable 77 by means of which the sensor pawl can effect the operation of a seat belt locking device as described with reference to Figure 1.

Operation of the latch arrangement of Figure 3 is as follows, With the backrest in a partly folded down position so that the striker pin 56 is at the position 56', and the lever 62 moved in the direction of the arrow B and the rotor 52 moved under the action of the spring 55 to the position 52', the sensor pawl 57 is withdrawn from its secure latching sensing position through its movement by the lever 62 through the lost motion link 74.

Withdrawal of the sensor pawl 57 in this way causes the inner wire of the cable 77 to be pulled to effect the locking of the seat belt retractor reel. Movement of the lever 62 also effects movement of the secondary pawl 72 through the lost motion link 75 so that the nose 70 of the pawl is clear of the path of the rotor 52 to allow the rotor to move to the position 52'. Movement of the backrest and thereby the striker pin in the direction of the arrow A, causes the pin 56 to strike a portion 78 of the cam surfaces of the rotor 52 and rotate the rotor anti-clockwise. During progressive movement of the pin 56 the cam surfaces of the rotor 52 slide over the pin 56 until the pin locates with the captive portion 58. With the pin 56 located with the captive portion 58, the lever 62 is moved counter to the direction indicated by the arrow B. This movement allows the nose 70 of the pawl 72 to locate with the captive portion 71 and causes rotation of the sensor pawl 57 whereby the nose 60 of the sensor pawl 57 locates with the captive portion 61. By this means the latch is securely locked which is sensed by the sensor pawl 57 which by its movement causes the seat belt locking device to be released via the cable 77. Release of the backrest is effected by movement of the lever 62 in the direction of the arrow B which firstly causes movement of the sensor pawl 57 and activation of the seat belt locking device with movement of the pawl 72 being delayed through the lost motion device. With the seat belt retractor reel having been thus locked continued movement of the lever 62 in the direction B the causes the nose 70 of the pawl 72 to be lifted clear of the captive portion 71 whereby the rotor 57 is allowed to rotate clockwise to release the pin 56 and allow the backrest to be folded down.

Claims (12)

1. Claims 1. A vehicle seat latch arrangement comprising a latch means to releasably secure a foldable component of the seat in its correct riding position to the vehicle body wherein the latch means is provided with a sensor to sense the secure latching of the seat component in its correct riding position and on so sensing the secure latching of the seat component to activate release mechanism to release a seat belt retractor reel locking device from a reversible locking position to an unlocking position to permit a seat belt web retained by the reel to be payed pot by the reel and the seat belt to be used.
2. 2. A vehicle seat latch arrangement as claimed in Claim 1 wherein the foldable seat component is the backrest of a bench seat accommodating a centre seat passenger.
3. 3. A vehicle seat latch arrangement as claimed in either Claim I or Claim 2 wherein the latch means is of the rotary type adapted to cooperate with a striker pin.
4. 4. A vehicle seat latch arrangement as claimed in any one of the preceding claims wherein the sensor with which the latch means is provided is a sprung loaded pawl.
5. 5. A vehicle seat latch arrangement as claimed in either of Claim 3 or Claim 4 wherein the rotor has cam surfaces including first and second captive surfaces.
6. 6. A vehicle seat latch arrangement as claimed in Claim 4 wherein the pawl is held by a blocking device until the rotor is in the secure latching position when the blocking device is caused to release the pawl by movement of the pin.
7. 7. A vehicle seat latch arrangement as claimed in any one of Claims 4 to 6 wherein a lever is connected to the pawl whereby movement of the lever releases the seat component from its secure latching.
8. 8. A vehicle seat latch arrangement as claimed in Claim 7 wherein the lever is connected to the pawl through a lost motion link.
9. 9. A vehicle seat latch arrangement as claimed in Claim 8 wherein the lever is also connected to a secondary sprung loaded pawl through a lost motion link for cooperation with a third captive portion of the cam surfaces of the rotor.
10. 10. A vehicle seat latch arrangement as claimed in Claim 9 wherein movement of the lever in a direction to move the sensor from a position in which it senses the secure latching of the seat component moves the sensor before it moves the secondary pawl to a position to release the latching of the seat component.
11. 11. A vehicle seat latch arrangement as claimed in any one of the preceding claims wherein the sensor activates the release mechanism solely through mechanical linkage.
12. 12. A vehicle seat latch arrangement substantially as herein described with reference to Figure 1 or to Figure 2 or to Figure 3.