GB1588867A - Seat reclining mechanism - Google Patents

Description

(54) SEAT RECLINING MECHANISM (71) We, H.R. TURNER (WIL LENHALL) LIMITED, of Holly Lane, Great Wyrley, Walsall, West Midlands WS6 6AJ, a British Company, do hereby declare the invention for which we pray that a Patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement.

This invention relates to a reclining mechanism for a vehicle seat to enable the backrest to be adjusted in inclination relative to the seat base.

According to the present invention we provide a reclining mechanism comprising a pair of hingedly connected parts, one of which is provided with a first set of teeth which extends arcuately about the hinge axis and the other of which is provided with a second set of teeth mounted for movement inwardly and outwardly with respect to said hinge axis between a locking position in which the two sets of teeth mesh to prevent relative hinging between the parts and a releasing position in which the sets of teeth are out of mesh to allow relative hinging, and a lever mounted pivotally on the mechanism and coupled pivotally to said second set of teeth by a link, which has pivotal connections with said lever and said second set respectively. to effect said inward and outward movement of said second set in response to pivoting of the lever, the arrangement being such that the pivotal connection between said link and said lever moves towards (and, optionally, beyond) a line joining the remaining two pivotal connections as the lever is pivoted in a direction which brings said second set towards the locking position.

Preferably when said sets of teeth are fully meshed. the pivotal connection between said link and said second set lies on, or overcentre with respect to, said line.

Preferably also said line extends substantially radially with respect to the hinge axis.

In one embodiment of the invention, the second set of teeth are mounted slidably on said other hinge part for movement in a radial direction with respect to the hinge axis. In another embodiment, the second set of teeth are pivoted to said other part and, when the teeth are meshed the line joining the pivotal connection between said second set and said other part and the pivotal connection between the link and said second set is at an angle of substantially 90" to the first-mentioned line.

Preferably, in the meshed position, the line joining the pivotal connections between the lever and the mechanism and the lever and the link and the line joining the pivotal connections between the second set of teeth and the link and between the lever and the link are collinear or no more than 20 from collinearity.

The invention will be described further with reference to the examples shown in the accompanying drawings, in which Figures 1, 2 and 3 are side views of three different embodiments of the invention.

Referring firstly to Figure 1, the inclination adjustment mechanism comprises a first plate 10 which may be attached to, or form part of the seat base of a vehicle seat and a second plate 12 which may be attached to or form part of the backrest. The two parts are connected together by a pivot 14 to allow relative hinging. The part 12 is provided along its lower edge with a set of teeth 16 which extend arcuately about the axis 14 in concentric relation with that axis. The individual teeth are of V-shape. The part 10 is provided with a set of teeth 18 formed on a link 20 which is pivoted at 22 so that the teeth 18 can be moved radially inwardly and outwardly relative to the axis between the illustrated position in which the teeth 16 and 18 are in mesh and prevent relative hinging between the parts 10, 12 and a position in which the teeth 16, 18 are out of mesh to allow relative hinging.

Such displacement is effected by a lever 24 pivoted at 26 and connected to the link 20 via an intermediate link 28 to form a toggle linkage, the link 28 having pivotal connections at 30 and 32 with the lever 24 and the link 20 respectively. A stop 34 on the part 10 defines the setting of the linkage when the teeth 16, 18 are fully meshed.

It will be noted that the line 36 joining the pivotal connections 26 and 32 is radial, i.e. it passes through the hinge axis 14, when the teeth are fully meshed and the line 38 joining the pivotal connections 22 and 32 is substantially perpendicular thereto.

Moreover the pivotal connection 30 lies on the line 36. This arrangement enables the mechanism to resist any tendency for the teeth 16, 18 to demesh when the backrest is subject to heavy loads as may occur in vehicle crash conditions. Naturally it would be undesirable for the mechanism to fail in such circumstances and allow the backrest to hinge relative to the seat base. Because of the mechanical advantage afforded by the toggle linkage, relatively large forces can be counteracted by a relatively weak spring arranged to bias the pivotal connection 30 towards the stop 34.

Although in Figure 1, the pivotal connection lies on the line 36 modification is possible such that the lines joining pivots 26 and 30 and pivots 30 and 32 respectively are non-collinear in the position of mesh. Preferably however the deviation from collinearity is no more than 20 . Also, when the teeth 16, 18 are fully meshed, the arrangement may be such that the pivotal connection 30 is slightly undercentre (i.e. to the right) with respect to the line 36 or overcentre. In the latter case, the relatively weak spring may not be needed.

Figure 2 illustrates a modification in which the adjustment mechanism components are reversed in that the teeth 16 are provided on the part 10 and the components 18, 20, 24 and 28 are provided on the part 12. In this embodiment, the lever pivots about the hinge axis 14.

Figure 3 illustrates a modification of Figure 2 in which the link 20 is replaced by a slidable element 20A having the teeth 18, the element 20A being provided with a lug 40 which engages in a slot (not shown) in a plate fast with the part 12 so as to guide the element radially.

In each embodiment. adjustment is achieved by turning the lever 24 clockwise to draw the teeth 18 out of mesh with the teeth 16. The backrest is then adjusted to the desired inclination and the lever 24 is allowed to return. conveniently under the action of spring loading. thus bringing the teeth 16, 18 back into mesh.

In practice, the mechanism will be duplicated on each side of the seat with the exception that only one lever 24 need be provided, the other mechanism having a link in place of the lever and means being provided, e.g. a rod or the like, to transmit turning of the lever from one side of the seat to the other to effect turning of the lastmentioned link.

WHAT WE CLAIM IS: 1. A reclining mechanism comprising a pair of hingedly connected parts, one of which is provided with a first set of teeth which extends arcuately about the hinge axis and the other of which is provided with a second set of teeth mounted for movement inwardly and outwardly with respect to said hinge axis between a locking in which the two sets of teeth mesh to prevent relative hinging between the parts and a releasing position in which the sets of teeth are out of mesh to allow relative hinging, and a lever mounted pivotally on the mechanism and coupled pivotally to said second set of teeth by a link, which has pivotal connection with said lever and said second set respectively, to effect said inward and outward movement of said second set in response to pivoting of said lever, the arrangement being such that the pivotal connection between said link and said lever moves towards (and, optionally, beyond) a line joining the remaining two pivotal connections as the lever is pivoted in a direction which brings said second set towards the locking position.

2. A reclining mechanism according to claim 1, in which, when said sets of teeth are fully meshed, the pivotal connection between said link arid said second set lies on, or overcentre with respect to, said line.

3. A reclining mechanism according to Claim 1 or 2, in which said line extends substantially radially with respect to the hinge axis.

4. A reclining mechanism according to anyone of Claims 1-3 in which the second set of teeth are mounted slidably on said other hinge part for movement in a radial direction with respect to the hinge axis.

5. A reclining mechanism according to any one of Claims 1-3 in which the second set of teeth are pivoted to said other part and, when the teeth are meshed, the line joining the pivotal connection between said second set and said other part and the pivotal connection between the link and said second set is at an angle of substantially 90" to the first-mentioned line.

6. A reclining mechanism according to anyone of Claims 1-5 in which the line joining the pivotal connections between the lever and the mechanism and the lever and the link and the line joining the pivotal connections between the second set of teeth

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. which the teeth 16, 18 are out of mesh to allow relative hinging. Such displacement is effected by a lever 24 pivoted at 26 and connected to the link 20 via an intermediate link 28 to form a toggle linkage, the link 28 having pivotal connections at 30 and 32 with the lever 24 and the link 20 respectively. A stop 34 on the part 10 defines the setting of the linkage when the teeth 16, 18 are fully meshed. It will be noted that the line 36 joining the pivotal connections 26 and 32 is radial, i.e. it passes through the hinge axis 14, when the teeth are fully meshed and the line 38 joining the pivotal connections 22 and 32 is substantially perpendicular thereto. Moreover the pivotal connection 30 lies on the line 36. This arrangement enables the mechanism to resist any tendency for the teeth 16, 18 to demesh when the backrest is subject to heavy loads as may occur in vehicle crash conditions. Naturally it would be undesirable for the mechanism to fail in such circumstances and allow the backrest to hinge relative to the seat base. Because of the mechanical advantage afforded by the toggle linkage, relatively large forces can be counteracted by a relatively weak spring arranged to bias the pivotal connection 30 towards the stop 34. Although in Figure 1, the pivotal connection lies on the line 36 modification is possible such that the lines joining pivots 26 and 30 and pivots 30 and 32 respectively are non-collinear in the position of mesh. Preferably however the deviation from collinearity is no more than 20 . Also, when the teeth 16, 18 are fully meshed, the arrangement may be such that the pivotal connection 30 is slightly undercentre (i.e. to the right) with respect to the line 36 or overcentre. In the latter case, the relatively weak spring may not be needed. Figure 2 illustrates a modification in which the adjustment mechanism components are reversed in that the teeth 16 are provided on the part 10 and the components 18, 20, 24 and 28 are provided on the part 12. In this embodiment, the lever pivots about the hinge axis 14. Figure 3 illustrates a modification of Figure 2 in which the link 20 is replaced by a slidable element 20A having the teeth 18, the element 20A being provided with a lug 40 which engages in a slot (not shown) in a plate fast with the part 12 so as to guide the element radially. In each embodiment. adjustment is achieved by turning the lever 24 clockwise to draw the teeth 18 out of mesh with the teeth 16. The backrest is then adjusted to the desired inclination and the lever 24 is allowed to return. conveniently under the action of spring loading. thus bringing the teeth 16, 18 back into mesh. In practice, the mechanism will be duplicated on each side of the seat with the exception that only one lever 24 need be provided, the other mechanism having a link in place of the lever and means being provided, e.g. a rod or the like, to transmit turning of the lever from one side of the seat to the other to effect turning of the lastmentioned link. WHAT WE CLAIM IS:

1. A reclining mechanism comprising a pair of hingedly connected parts, one of which is provided with a first set of teeth which extends arcuately about the hinge axis and the other of which is provided with a second set of teeth mounted for movement inwardly and outwardly with respect to said hinge axis between a locking in which the two sets of teeth mesh to prevent relative hinging between the parts and a releasing position in which the sets of teeth are out of mesh to allow relative hinging, and a lever mounted pivotally on the mechanism and coupled pivotally to said second set of teeth by a link, which has pivotal connection with said lever and said second set respectively, to effect said inward and outward movement of said second set in response to pivoting of said lever, the arrangement being such that the pivotal connection between said link and said lever moves towards (and, optionally, beyond) a line joining the remaining two pivotal connections as the lever is pivoted in a direction which brings said second set towards the locking position.

2. A reclining mechanism according to claim 1, in which, when said sets of teeth are fully meshed, the pivotal connection between said link arid said second set lies on, or overcentre with respect to, said line.

3. A reclining mechanism according to Claim 1 or 2, in which said line extends substantially radially with respect to the hinge axis.

4. A reclining mechanism according to anyone of Claims 1-3 in which the second set of teeth are mounted slidably on said other hinge part for movement in a radial direction with respect to the hinge axis.

5. A reclining mechanism according to any one of Claims 1-3 in which the second set of teeth are pivoted to said other part and, when the teeth are meshed, the line joining the pivotal connection between said second set and said other part and the pivotal connection between the link and said second set is at an angle of substantially 90" to the first-mentioned line.

6. A reclining mechanism according to anyone of Claims 1-5 in which the line joining the pivotal connections between the lever and the mechanism and the lever and the link and the line joining the pivotal connections between the second set of teeth

and the link and between the lever and the link are collinear or no more than 20 from collinearity.

7. A reclining mechanism substantially as hereinbefore described with reference to, and as shown in, any one of Figures 1-3 of the accompanying drawings.