Hinge assembly for a vehicle rear seat

Abstract: A hinge assembly (30) for a backrest (16) of a rear seat (12) of a vehicle in which the backrest can pivot between a substantially upright position and a substantially horizontal position and in which the backrest can be latched at one edge (24) in the substantially upright position, the hinge assembly comprising a first member (32) securable to the opposed edge (18) of the backrest; a second member (34) securable to a body portion (36) of the vehicle; a third member (38) positioned between the first member and the second member; a fourth member (40) positioned adjacent the third member and below the first member; a first pin (56) secured to the third member about which the first member can pivot; a second pin (58) secured to the second member about which the third member can pivot; a third pin (60) secured to the third member about which the fourth member can pivot; and a fourth pin (62) secured to the second member about which the fourth member can pivot; wherein the axes (A,B,C,D) of the pins are substantially parallel; wherein the edge of the first member directed towards the fourth member has teeth (50); and wherein the edge of the fourth member directed towards the first member has teeth (46); the relative positioning of the pins being such that when a force is applied to the first member in a direction which attempts to move the backrest to the horizontal position whilst the backrest is latched in the upright position, the first pin moves to pivot the third member about the second pin, whereby the third pin moves to pivot the fourth member about the fourth pin to bring the teeth on the first and fourth members into engagement to lock the hinge assembly.

Description: The present invention relates to a hinge assembly for split folding backrests for the rear seat of a motor vehicle. Motor vehicles are now commonly produced with a rear seat which is split into two parts. Hinges are provided towards the bottom edge of the backrest of each part of the rear seat to allow each backrest to pivot between its normal substantially vertical (upright) position and a substantially horizontal position across the associated seat cushion. The hinges usually include a hinge arrangement at the split between the two backrests. Catches are provided on the edges of the backrests remote from the split to lock the backrests in their vertical position. Each catch can be released to allow its associated backrest to pivot. Where a luggage compartment is positioned directly behind the rear seat it is preferable to provide a locking arrangement at the hinge at the split. The locking arrangement locks the hinge to reduce the risk of damage being caused to the backrests, hinges and/or catches should a heavy load in the luggage compartment move and strike the backrests. EP-A-0,474,368 discloses a hinge at the split between the backrests which has a locking arrangement which is engaged when each backrest is in its normal substantially vertical position. The releasing system for the locking arrangement is associated with the catch for the backrest such that the catch and the locking arrangement are released substantially simultaneously. This release system is difficult to assemble, and is not reliable. EP-A-0,577,517, EP-A-0,564,962, and US 4,475,769 all disclose locking arrangements which are activated upon a predetermined deceleration of the vehicle. These systems are not reliable, and do not allow for movement of heavy loads under other circumstances. It is an object of the present invention to provided an improved locking arrangement for the hinge assembly at the split in the backrests of the rear seats. To this end, a hinge assembly in accordance with the present invention for a backrest of a rear seat of a vehicle in which the backrest can pivot between a substantially upright position and a substantially horizontal position and in which the backrest can be latched at one edge in the substantially upright position, comprises a first member securable to the opposed edge of the backrest; a second member securable to a body portion of the vehicle; a third member positioned between the first member and the second member; a fourth member positioned adjacent the third member and below the first member; a first pin secured to the third member about which the first member can pivot; a second pin secured to the second member about which the third member can pivot; a third pin secured to the third member about which the fourth member can pivot; and a fourth pin secured to the second member about which the fourth member can pivot; wherein the axes of the pins are substantially parallel; wherein the edge of the first member directed towards the fourth member has teeth; and wherein the edge of the fourth member directed towards the first member has teeth; the relative positioning of the pins being such that when a force is applied to the first member in a direction which attempts to move the backrest to the horizontal position whilst the backrest is latched in the upright position, the first pin moves to pivot the third member about the second pin, whereby the third pin moves to pivot the fourth member about the fourth pin to bring the teeth on the first and fourth members into engagement to lock the hinge assembly. The present invention also includes a backrest including a hinge assembly as claimed herein, and a rear seat for a vehicle having a backrest including a hinge assembly as claimed herein. The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a cut-away view of a motor vehicle having a rear seat with split folding backrests and hinge assembly in accordance with the present invention; Figure 2 is a rear view of the split folding backrests and hinge assembly of Figure 1; Figure 3 is an enlarged view of the area labelled III in Figure 2 when viewed from the front of the seat; Figure 4 is a cross-sectional view on the line IV-IV of Figure 3 with the backrest in its substantially vertical position; Figure 5 is a view similar to that of Figure 4 with the backrest in its substantially horizontal position; and Figure 6 is a view similar to that of Figure 4 with the backrest in its substantially vertical position but when subjected to a substantially horizontal force. Referring to Figures 1 and 2 of the drawings, a motor vehicle is shown 10 having a rear seat 12. The rear seat 12 comprises a seat cushion 14 and a pair of folding backrests 16 with a split 18 therebetween. Each backrest 16 comprises a substantially rigid support portion 20, a catch 22 at the edge 24 remote from the split 18, and a hinge pin 26 at the edge 24. Each catch 22 can latch with a portion 28 of the vehicle body to releasably lock the associated backrest 16 in a normal substantially vertical (or upright) position. Each catch 22 may be such that the associated backrest 16 can be latched in any one of four different upright positions, each upright position being at a small angle relative to the next adjacent upright position. Release means (not shown) for the catches 22 can be any known arrangement. Each hinge pin 26 also engages the portion 28 of the vehicle body, and along with a hinge assembly 30 (details of which are described below) at the split 18, provides a pivot axis A for each backrest 16 to allow each backrest to fold to a substantially horizontal position across its associated part of the seat cushion 14. The present invention lies in the arrangement of the hinge assembly 30, which will now be described in greater detail with reference to Figures 3 to 6. The hinge assembly 30 comprises, for each backrest 16, a first plate-like member 32 which is integral with (as shown), or secured to, the support portion 22 of the backrest; a second plate-like member 34 which is secured to the body 36 of the motor vehicle 10; a third plate-like member 38 which is pivotally mounted on the second plate-like member; and a fourth plate-like member 40 which is pivotally mounted on the second plate-like member. The third plate-like member 38 is positioned between the first plate-like member 32 and the second plate-like member 34. The fourth plate-like member 40 is positioned adjacent the third plate-like member 38 and below the first plate-like member 32. The first plate-like member 32 is pivotally mounted on the third plate-like member 38 by a first pin 56 which is secured to the third plate-like member. The axis of the first pin 56 normally aligns with the axis A of the hinge pins 26. The first plate-like member 32 has a number of teeth 50 at one edge directed downwards towards the fourth plate-like member 40. The third plate-like member 38 is pivotally mounted on the second plate-like member 34 by a second pin 58 which is secured to the second plate-like member. The fourth plate-like member 40 is pivotally mounted on the third plate-like member 38 by a third pin 60 secured to the third plate-like member. The fourth plate-like member 40 can also pivot about a fourth pin 62 which is secured to the second plate-like member 34 adjacent the body portion 36. The fourth plate-like member 40 is biased to a normal or rest position against the body portion 36 by a spring 44. The fourth plate-like member 42 has a pair of teeth 46 at its edge remote from the fourth pin 62 directed substantially upwards towards the teeth 50 on the first plate-like member 32. The first pin 56 has an axis corresponding to axis A. The second pin 58 has an axis B. The third pin 60 has an axis C. The fourth pin 62 has an axis D. The axes A-D of the pins 56-62 are substantially parallel. The relative positioning of the pins 56-62 is such that the third plate-like member 38 acts as a lever such that any movement of the first pin 56 about the axis B of the second pin 58 causes movement of the third pin 60 about the axis B. Any movement of the third pin 60 about the axis B causes the fourth plate-like member 40 to pivot about the fourth pin 62. In the normal upright position of the backrest 16, with the backrest latched in place by its catch 22, the associated hinge assembly 30 has the layout as shown in Figure 4. The fourth plate-like member 40 is biased against the body portion 36 by the spring 44. If the catch 22 is released, the backrest 16 is free to pivot about axis A of the first pin 56 and the associated hinge pin 26, as the first plate-like member 32 pivots about the first pin 56. This is depicted in Figure 5. Figure 6 depicts the case where the backrest 16 is in its substantially upright position and is latched in place by its catch 22, and the backrest, and hence the first plate-like member 32, is subjected to a force F. Such a force may be generated when a load or the like strikes the rear of the rear seat 12. In this instance, the force F moves the first plate-like member 32 such that the axis of the first pin 56 moves from position A to position A' about the axis B of the second pin 58. Because the first pin 56 is secured to the third plate-like member 38, the third plate-like member pivots about the axis B of the second pin 58 and the axis of the third pin 60 moves from position C to position C' about the axis B. Such movement of the third pin 60 causes the fourth plate-like member 40 to pivot about the axis D of the fourth pin 62 against the bias of the spring 44. Such movement of the fourth plate-like member 40 brings the teeth 46 on the fourth plate-like member into engagement with the teeth 50 on the first plate-like member 32 to lock the hinge assembly 30 as the fourth plate-like member is effectively wedged between the first plate-like member and the fourth pin 62. This locking arrangement substantially prevents any further movement of the first plate-like member 32, and so substantially prevents any further movement of the backrest 16 due to the force F. Removal of the force F brings the axis of the first pin 56 back to position A and the axis of the third pin 60 back to position C, and the spring 44 restores the fourth plate-like member 40 to its rest position as shown in Figure 4. The first plate-like member 32 is shown as having four teeth 50. This number corresponds to the number of possible upright positions of the backrest 16, and allows for changes in the initial relative position of the first plate-like member 32 to the fourth plate-like member 40. This substantially ensures engagement of teeth 46 with teeth 50 irrespective of the initial upright position of the backrest 16. The locking arrangement of the present invention is only effective when the backrest is subjected to a force. It is not dependent on detection of a predetermined deceleration of the vehicle. It is not locked during normal usage of the vehicle and therefore does not need to be released in order to fold down the backrest. The hinge assembly of the present invention is also simpler and easier to manufacture and assemble, when compared to the known prior art. In the above described arrangement, and as shown in the drawings, the hinge assembly 30 has parts which are common to each backrest 16. For example, the first pin 56, the third pin 60, the fourth pin 62, and the fourth plate-like member 40 are common parts for the hinge assembly for each backrest 16. It will be appreciated that these common parts may be split such that a separate hinge assembly in accordance with the present invention may be provided for each backrest 16.

Claims: A hinge assembly (30) for a backrest (16) of a rear seat (12) of a vehicle in which the backrest can pivot between a substantially upright position and a substantially horizontal position and in which the backrest can be latched at one edge (24) in the substantially upright position, the hinge assembly comprising a first member (32) securable to the opposed edge (18) of the backrest; a second member (34) securable to a body portion (36) of the vehicle; a third member (38) positioned between the first member and the second member; a fourth member (40) positioned adjacent the third member and below the first member; a first pin (56) secured to the third member about which the first member can pivot; a second pin (58) secured to the second member about which the third member can pivot; a third pin (60) secured to the third member about which the fourth member can pivot; and a fourth pin (62) secured to the second member about which the fourth member can pivot; wherein the axes (A,B,C,D) of the pins are substantially parallel; wherein the edge of the first member directed towards the fourth member has teeth (50); and wherein the edge of the fourth member directed towards the first member has teeth (46); the relative positioning of the pins being such that when a force is applied to the first member in a direction which attempts to move the backrest to the horizontal position whilst the backrest is latched in the upright position, the first pin moves to pivot the third member about the second pin, whereby the third pin moves to pivot the fourth member about the fourth pin to bring the teeth on the first and fourth members into engagement to lock the hinge assembly. A hinge assembly as claimed in Claim 1, wherein in a vertical direction the first pin (56) is above the second pin (58) which is above the third pin (60) which is above the fourth pin (62); and wherein in a horizontal direction the third pin is positioned between the fourth pin and the first pin and the first pin is positioned between the third pin and the second pin. A hinge assembly as claimed in Claim 1 or Claim 2, wherein biasing means (44) acts on the fourth member (40) to bias the teeth (46) on the fourth member away from the teeth (50) on the first member (32), the biasing force being overcome when the force is applied to the first member. A hinge assembly as claimed in Claim 3, wherein the biasing means is a spring (44) which is attached to the fourth member (40) and which is attachable to the body portion (36) of the vehicle. A hinge assembly as claimed in any one of Claims 1 to 4, wherein each of the members (32,34,38,40) is substantially plate-like. A rear seat of a vehicle comprising a pair of backrests (20) each of which can pivot between a substantially upright position and a substantially horizontal position, each backrest including a catch (22) at one edge to latch the backrest in the substantially upright position and a hinge assembly (30) as claimed in any one of Claims 1 to 5 at the opposed edge. A backrest assembly for a rear seat of a vehicle in which the backrest (20) can pivot between a substantially upright position and a substantially horizontal position, the backrest including a catch (22) at one edge to latch the backrest in the substantially upright position and a hinge assembly (30) as claimed in any one of Claims 1 to 5 at the opposed edge.

Inventors: WIECLAWSKI STANISLAW ANDRZEJ, WIECLAWSKI, STANISLAW ANDRZEJ
Applicants: LEAR CORP, LEAR CORPORATION
Application year: 1996
Main classification: B60N2
IPC codes: B60N2