WO2007036691A1

WO2007036691A1 - Recliner mechanism

Info

Publication number: WO2007036691A1
Application number: PCT/GB2006/003375
Authority: WO
Inventors: Michael Drew
Original assignee: Atl Engineering (Eu) Limited
Priority date: 2005-09-29
Filing date: 2006-09-13
Publication date: 2007-04-05
Also published as: GB2430616A; GB0519831D0

Abstract

A recliner mechanism for a seat having a seat cushion and an adjustable squab includes a stationary hinge member (28) for connection to the seat cushion, an adjustable hinge member (12) for connection to the squab, and an angular position adjuster (16, 42, 44) in the form of a ratchet mechanism. The ratchet mechanism includes a first gear (42), a second gear (44) and a ratchet element (16) that is adjustable between a locked configuration in which it engages the first and second gears to prevent adjustment of the hinge members, and an unlocked configuration in which it disengages the first and second gears to allow angular adjustment of the hinge members.

Description

RECLINER MECHANISM

The present invention relates to a recliner mechanism for vehicle seats and similar applications. The invention also relates to a vehicle seat including such a mechanism.

Many vehicle seats include a recliner mechanism that allows the angle of the squab (or seat back) to be adjusted relative to the seat cushion (or base), so that the occupant can be seated in maximum comfort. This is important as the body shape and size of occupants can vary greatly. It is also desirable to have a facility for reclining the seat squab, so that the occupant can rest in a more horizontal position.

The recliner mechanism naturally has to be able to withstand a number of forces during normal use including in particular the rearwards force caused by a passenger leaning against the squab.

However, for safety and to comply with worldwide legislation, it also has to be able to withstand the much greater forces that might be generated if the vehicle is involved in a collision. In particular, if the squab carries the upper anchoring point for the seat belt, a very large forwards force may be generated in the event of a frontal collision, owing to the inertia of the passenger. Such transient forces may be many times greater than the forces experienced during normal usage and the recliner mechanism must be able to withstand them without collapsing.

There are two main types of recliner mechanism in common use. The first of these uses a ratchet mechanism to control the position of the squab. The ratchet mechanism can be released using a lever, allowing the angle of the squab to be adjusted. The lever is then released to re-engage the ratchet, locking the squab in the chosen position.

The second type of recliner mechanism uses a gear mechanism that has a continual mesh and provides a continuously variable adjustment range. These mechanisms are normally operated by manual hand wheels or electric motors. By turning the hand wheel or operating the electric motor the squab can be adjusted backwards or forwards. During adjustment the gear mechanism remains constantly in mesh. The recliner mechanism can therefore be stopped in any position within a continuously variable range of adjustment.

The present invention relates to the first type of recliner mechanism, which uses a ratchet mechanism for locking the squab at the desired angle.

In one such recliner mechanism described in DE-OS-2931873 , the squab is attached to a pivot arm that is provided with a set of ratchet teeth. Those teeth are engaged by a locking plate having a complementary set of teeth. The locking plate can be moved away from the pivot arm to disengage the two sets of teeth, allowing the angle of the seat back to be adjusted. The locking plate can then be moved back towards the pivot arm, to engage the teeth and lock the seat back in position.

The recliner mechanism described in DE-OS-2931873 has numerous disadvantages. First, because any forces exerted on the squab are carried by only a few teeth on the ratchet element, the mechanism is weak and may collapse in the event of a collision. Further, the mechanism is likely to suffer from significant play both in the ratchet element and in the seat pivot, which may cause the seat back to wobble particularly when the components of the recliner mechanism become worn. The mechanism is also rather large and heavy and cannot be accommodated within a compact, lightweight unit.

It is an object of the present invention to provide a recliner mechanism that mitigates at least some of the disadvantages of prior art recliner mechanisms.

According to one aspect of the present invention there is provided a recliner mechanism for a seat having a seat cushion and an adjustable squab, the mechanism including a stationary hinge member for connection to the seat cushion, an adjustable hinge member for connection to the squab, and an angular position adjuster in the form of a ratchet mechanism, wherein the ratchet mechanism includes a first gear, a second gear and a ratchet element that is adjustable between a locked configuration in which it engages the first and second gears to prevent adjustment of the hinge members, and an unlocked configuration in which it disengages the first and second gears to allow angular adjustment of the hinge members. The provision of first and second gears greatly increases the strength of the ratchet mechanism, as any loads applied to the squab are carried by a larger number of teeth. Also, because the ratchet element engages two separate gears at different locations, play is significantly reduced. This arrangement also allows a strong and reliable recliner mechanism to be accommodated within a relatively light, compact unit.

Advantageously, the first and second gears are connected to one of the hinge members, and the ratchet element is carried by the other hinge member. Preferably, the first and second gears are connected to the adjustable hinge member, and the ratchet element is carried by the stationary hinge member. In this latter arrangement, the ratchet element does not rotate with the adjustable hinge member, and the effect of the ratchet element's weight does not therefore change as the seat is adjusted. Any controls for operating the ratchet mechanism will also remain stationary.

The first and second gears are preferably substantially coaxial. Advantageously, the first and second gears lie in substantially the same plane. This avoids twisting moments in the mechanism. Advantageously, at least one of the gears is formed by semi-shearing, or by a similar process.

Advantageously, one of the gears is an internal gear and the other is an external gear. The ratchet element preferably engages the first and second gears on opposed sides thereof. The separation of the engagement points so that they are located on opposed sides of the gears (and therefore on opposite sides of the pivot axis) greatly increases the strength of the ratchet mechanism and significantly reduces play, allowing the recliner to be accommodated within a very light and compact unit.

Advantageously, the ratchet element is constructed and arranged for linear movement. Preferably, the ratchet element is arranged to slide between parallel guide elements.

The recliner mechanism may include a compensator element for reducing play in the mechanism. The compensator element preferably comprises a wedge-shaped element accommodated in a recess between the ratchet element and one of the parallel guide members. The recliner mechanism preferably includes a resiliently biassing element that acts on the compensator element. The compensator element removes play between the ratchet element and the guide elements and compensates for manufacturing tolerances and wear of the components. It therefore significantly reduces play in the recliner unit as a whole.

The recliner mechanism may include a drive element for controlling movement of the ratchet element. The drive element preferably comprises a rotatable cam.

According to another aspect of the invention there is provided a seat including a seat cushion, an adjustable squab and arecliner mechanism according to any one of the preceding statements of invention.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic side view of a vehicle seat having a recliner mechanism;

Figure 2 is an exploded isometric view of a recliner mechanism according to the invention;

Figure 3 is an isometric view showing a first side of the recliner mechanism with some parts removed;

Figure 4 is an isometric view showing a second side of the recliner mechanism with some parts removed;

Figure 5 is a side view of the recliner mechanism, showing hidden details;

Figure 6 is a sectional front view of the recliner mechanism on line VI-VI of Fig. 5; and

Figure 7 is a sectional top view of the recliner mechanism on line VII-VII of Fig. 5.

The vehicle seat shown schematically in Figure 1 includes a seat cushion 2, which is the part the occupant sits on, a seat squab (or backrest) 4, and a recliner mechanism 6 that connects the squab to the cushion and allows the angle of the squab 4 to be adjusted relative to the cushion

2.

The recliner mechanism 6 shown in Figures 2 to 7 comprises a cushion plate 10 for connection to the frame of the seat cushion 2 and a squab plate 12 for connection to the squab 4, which is pivotable about a pivot axis 14 relative the cushion plate. A ratchet plate 16 is arranged for sliding movement between a locked position in which adjustment of the recliner mechanism is prevented, and an unlocked position in which adjustment is allowed. Sliding movement of the ratchet plate 16 is controlled by a cam 18, which can be operated using a lever 20. Play (chuck) in the mechanism is controlled by a wedge-shaped compensator 22, which is acted on by a biassing spring 24. The recliner mechanism is held together by a squab clamp plate 26, a cushion clamp plate 28, two E-clips 30 and four tubular rivets (not shown).

Some parts have been omitted from Figures 3 and 4 to show internal details of the recliner mechanism. In particular, in Figure 3 the cushion clamp plate 28 has been omitted, and in Figure 4 the cushion plate 10, the squab clamp plate 26, the lever 20 and one of the E-clips 30 have been omitted.

The cushion plate 10 is a fine blanked component having a semi-sheared recess 34 formed on its inner face, to receive the ratchet plate 16. The recess 34 has two parallel sides, which guide sliding movement of the ratchet plate. The upper and lower ends of the recess are curved, hi the centre of the cushion plate 10 is a circular hole 36 that provides a first bearing for the cam 18. Two holes 38 are provided at the bottom of the plate to receive two of the tubular rivets.

The squab plate 12 is also a fine blanked component, having an annular recess 40 formed on its inner face by semi-shearing. The squab plate carries two sets of gear teeth 42,44. The teeth of the first set of teeth 42 are provided around the periphery of a lower part of the squab plate and extend outwards. The teeth of the second set of teeth 44 are formed on the outer periphery of the annular recess and extend inwards, hi the centre of the squab plate is a circular hole 46 that provides a second bearing for the cam 18. Two holes 48 are provided at the top of the squab plate 12 for two of the tubular rivets.

The ratchet plate 16 is located within the recess 34 in the cushion plate and has two parallel side edges 50 that engage the edges of the recess, allowing sliding movement. One side edge of the ratchet plate 16 also includes a wedge-shaped recess 52, allowing the compensator 22 to be accommodated between that edge and the corresponding edge of the cushion plate recess 34. At the lower end of the wedge-shaped recess 52 is a roughly triangular recess 54 that accommodates the biassing spring 24.

The upper edge of the ratchet plate 16 includes a semi-sheared external tooth form 56 for engaging the inwards-facing teeth of the second gear set 44 on the squab plate 12. The external tooth form 56 is offset from the plane of the ratchet plate, so that it can be accommodated within the annular recess 40 formed on the inner face of the squab plate. The lower part of the ratchet plate is also offset and includes a set of inwards-facing teeth 58 for engaging the external teeth of the first gear set 42 on the squab plate 12.

When the ratchet plate 16 is in the position shown in Figs. 3-5 both sets of teeth 56,58 engage the corresponding teeth 42,44 on the squab plate 12, so locking the ratchet mechanism and preventing reclining movement of the seat. However, if the ratchet plate 16 is moved downwards from that position both sets of teeth will disengage, so unlocking the mechanism to allow reclining movement of the seat.

An irregular hole 60 is provided in the centre of the ratchet plate 16. The inwards-facing surface of the hole acts as a cam surface and is engaged by the cam 18 to control movement of ratchet plate 16 and locking/unlocking operation of the recliner mechanism.

As mentioned above, the wedge-shaped compensator 22 is accommodated in the recess 52 formed between the ratchet plate 16 and the squab plate 12. The side walls of the compensator and the recess 52 are inclined at an angle of approximately 2°-7°, preferably approximately 4°. The biassing spring 24 is accommodated within the triangular recess 54 below the compensator 22 and urges the compensator upwards so that it is driven as far as possible into the recess 52. This produces a wedging action, which prevents lateral movement of the ratchet plate 16 relative to the squab plate 12 and thus eliminates play (chuck) from the mechanism. As the components of the mechanism wear during use, the compensator 22 is driven further into the recess 52 to ensure that there is no play.

The cam 18 includes two cylindrical bearing surfaces 62 that are seated in the complementary bearing surfaces provided by the circular holes 36,46 in the squab plate 12 and the cushion plate 10. Between these two bearing surfaces an eccentric cam element 64 is provided, which engages the irregular hole 60 in the ratchet plate. The eccentric cam element 64 and the irregular hole 60 are shaped so that as the cam 18 rotates the cam element 64 remains in engagement with the hole 60, either above or below the rotational axis of the cam. This eliminates play between the cam 18 and the ratchet plate 16 and allows the cam to drive the ratchet plate upwards (into engagement) or downwards (out of engagement), as required. The cam 18 is located in position by a pair of E-clips 30 that engage peripheral grooves 66 towards the ends of the cam and lie against the outer faces of the cushion plate 10 and the squab plate 12. One end 68 of the cam 18 extends outwards beyond the cushion plate 10 and is engaged by the operating lever 20. A pair of flats 70 are formed on either side of the extending end part 68 of the cam, which are engaged by a correspondingly shaped hole 72 in one end of the lever 20, allowing rotational drive to be transmitted between the lever 20 and the cam 18.

The cushion clamp plate 28 has two holes 74 near its lower edge through which pass a pair of tubular rivets (not shown) to clamp it onto the cushion plate 10. Fixing bolts (not shown) can be inserted through the tubular rivets to attach the recliner mechanism to the frame of the seat cushion. The cushion clamp plate 28 includes an offset arcuate flange 76 that overhangs the lower edge of the squab plate 12 to stop the mechanism separating in use, whilst still allowing the squab plate to rotate. The cushion clamp plate also includes a parallel-sided recess 78 on its inner face, which accommodates the lower part of the ratchet plate 16 and assists in guiding movement of the ratchet plate.

The squab clamp plate 26 is similar to the cushion clamp plate 28 and has two holes 80 through which pass a pair of tubular rivets (not shown) that clamp it onto the squab plate 12. Fixing bolts (not shown) can be inserted through the tubular rivets to attach the recliner mechanism to the frame of the squab. The squab clamp plate 26 includes an offset arcuate flange 82 that overhangs the upper edge of the cushion plate 10 to stop the mechanism separating in use, whilst still allowing the squab plate 12 to rotate relative to the cushion plate 10.

In order to adjust the recliner mechanism, the lever 20 is rotated from the locked position shown in the drawings through an angle of approximately 30° to an unlocked position. The cam 18 rotates with the lever, driving the ratchet plate 16 downwards from the position shown in Figs. 3-5. This unlocks the ratchet mechanism and allows the position of the squab to be adjusted. The squab is moved to the desired angle and the recliner mechanism is then locked in the selected position by rotating the lever 20 back to the locked position. Alternatively, a spring may be provided to return the lever to the locked position. The cam 18 again rotates with the lever 20, driving the ratchet plate 16 upwards so that both sets of teeth 56,58 reengage the corresponding teeth 42,44 on the squab plate 12.

Movement of the ratchet plate 16 is guided by the parallel-sided recesses 34,78 in the cushion plate 10 and the cushion clamp plate 28 respectively. The compensator 22 slides up and down with the ratchet plate 16, but is continuously urged upwards into the wedge-shaped recess 52 by the spring 54, to remove any lateral play between the ratchet plate 16 and the cushion plate 10. This ensures that the recliner mechanism as a whole has very little play, even when the components become worn after prolonged use.

Because the ratchet plate 16 engages the first and second gears on opposite sides of the pivot axis, any loads applied to the recliner mechanism are carried by the ratchet plate rather than the pivot axle (the cam 18). These engagement points are widely spaced, giving the mechanism great strength. Furthermore, because the position of the mechanism is controlled only by the ratchet plate, wear in the cam bearings does not cause play. As play in the ratchet plate is controlled by the compensator 22, there is very little play in the recliner mechanism as a whole.

It should be understood that the recliner mechanism described above and shown in the drawings represents only one exemplary embodiment of the invention as defined by the claims. Various modifications of the invention are of course possible, as will be apparent to a person skilled in the art. For example, although the first and second gears 42, 44 shown hi the drawings have finely-spaced teeth that are set at an angular separation of approximately 4°, the teeth could be spaced more closely if a finer degree of adjustment is required, or further apart. If only a fewpositions of adjustment are required (for example, upright and reclined), very few teeth may be required.

Claims

1. A recliner mechanism for a seat having a seat cushion and an adjustable squab, the mechanism including a stationary hinge member for connection to the seat cushion, an adjustable hinge member for connection to the squab, and an angular position adjuster in the form of a ratchet mechanism, wherein the ratchet mechanism includes a first gear, a second gear and a ratchet element that is adjustable between a locked configuration in which it engages the first and second gears to prevent adjustment of the hinge members, and an unlocked configuration in which it disengages the first and second gears to allow angular adjustment of the hinge members.

2. A recliner mechanism according to claim 1 , in which the first and second gears are connected to one of the hinge members, and the ratchet element is carried by the other hinge member.

3. A recliner mechanism according to claim 2, in which the first and second gears are connected to the adjustable hinge member, and the ratchet element is carried by the stationary hinge member.

4. A recliner mechanism according to any one of the preceding claims, in which the first and second gears are substantially coaxial.

5. A recliner mechanism according to any one of the preceding claims, in which the first and second gears lie in substantially the same plane.

6. A recliner mechanism according to any one of the preceding claims, in which at least one of the gears is formed by semi-shearing.

7. A recliner mechanism according to any one of the preceding claims, in which one of the gears is an internal gear and the other is an external gear.

8. A recliner mechanism according to claim 7, in which the ratchet element engages the first and second gears on opposed sides thereof.

9. A recliner mechanism according to any one of the preceding claims, in which the ratchet element is constructed and arranged for linear movement.

10. A recliner mechanism according to claim 9, in which the ratchet element is arranged to slide between parallel guide elements.

11. A recliner mechanism according to claim 10, including a compensator element for reducing play in the mechanism.

12. A recliner mechanism according to claim 11, in which the compensator element comprises a wedge-shaped element accommodated in a recess between the ratchet element and one of the parallel guide members.

13. A recliner mechanism according to claim 12, including a resiliently biassing element that acts on the compensator element.

14. A recliner mechanism according to any one of the preceding claims, including a drive element for controlling movement of the ratchet element.

15. A recliner mechanism according to claim 14, in which the drive element comprises a rotatable cam.

16. A seat including a seat cushion, an adjustable squab and a recliner mechanism according to any one of the preceding claims.